Scielo RSS <![CDATA[Salud mental]]> http://www.scielo.org.mx/rss.php?pid=0185-332520090001&lang=pt vol. 32 num. 1 lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.org.mx/img/en/fbpelogp.gif http://www.scielo.org.mx <![CDATA[<b>Psychiatry NOS (not otherwise specified)</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0185-33252009000100001&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>Melatonin reduces neuronal loss and cytoskeletal deterioration</b>: <b>implications for Psychiatry</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0185-33252009000100002&lng=pt&nrm=iso&tlng=pt This review article summarizes the potential role of circadian rhythmicity and melatonin in psychiatric disorders. The melatonin rhythm, with high blood levels at night and low values during the day, is a reflection of the biological clock, i.e., the suprachiasmatic nucleus (SCN). The SCN receive information about the prevailing light: dark conditions from specialized ganglion cells (only 1-2% of the total ganglion cells) in the retina. These unique cells contain a newly-discovered photopigment, melanopsin, which responds to a rather narrow band width of light that peaks at roughly 480 nm. The axons of these ganglion cells project via the retinohypothalamic tract through the optic nerve to the SCN, located just above the optic chiasm in the anterior hypothalamus. Via this pathway, light detected by the retina synchronizes the circadian clock to precisely 24 hours. In the absence of light, i.e., darkness, the SCN signals the pineal gland to produce melatonin via a complex neural pathway that involves fibers that project from the hypothalamus to the preganglionic sympathetic neurons in the intermediolateral cell column of the upper thoracic cord. Axons of these neurons exit the spinal cord to eventually synapse on neurons in the superior cervical ganglia. Then, postganglionic fibers convey the information to the pineal gland mediating the nighttime rise in melatonin synthesis. Because melatonin is only elevated at night, it is referred to as the <<chemical expression of darkness>>. Disturbances in the rhythmicity of the biological clock and/or the melatonin rhythm likely contribute to psychophysiological disturbances and mood disorders. Major disturbances occur in circadian rhythmicity when light, which activates the SCN and inhibits melatonin production, is imposed during the normal dark period. Thus, even brief periods of light at night are readily detected by the specialized ganglion cells mentioned above; this sets off a chain of events that alter biological clock physiology and depresses nighttime melatonin levels when they should be elevated. Depressed circulating melatonin levels at night provide misinformation to all cells that can <<read>> the message. This misinformation contributes to alterations in mood and negative psychological feelings of well-being. Melatonin has several major functions which probably assist in protecting humans from psychiatric illnesses. This indoleamine is widely known as a sleep-promoting factor. As such, it reduces the latency to sleep onset and improves sleep hygiene. Melatonin has been tested for its beneficial effects on sleep in children with neurodevelopmental disabilities, in individuals with delayed sleep phase syndrome and in elderly patients with insomnia. In each of these situations, melatonin has proven to be beneficial. Sleep disturbances are often associated with and probably contribute to psychiatric illness. Melatonin is also a potent free radical scavenger and antioxidant. It, as well as several of its metabolites, are powerful protectors against oxidative stress and free radical-mediated, mitochondrial-dependent cellular apoptosis. Melatonin seems to be particularly effective in protecting the brain from oxidative mutilation and loss of cells resulting from apoptosis. Given that a variety of neurodegenerative diseases, e.g., Alzheimer disease, parkinsonism, amyotrophic lateral sclerosis, have a free radical component, it is assumed that melatonin may be useful in fores talling the consequences of these debilitating conditions and improving the psychological makeup of these patients. Preliminary clinical trials suggest melatonin will be useful in this regard. A major action of melatonin in the Central Nervous System is protection of the neuronal cytoskeleton from oxidative damage. Structural damage to the cytoskeleton is consequential in the function of neurons and is not uncommonly associated with psychological illness and with neurodegenerative diseases. For example, tauopathies (tau is an important cytoskeletal protein) contribute to neuropsychiatric disorders. Damage to the tau protein, resulting from the hyperphos-phorylation of this important molecule, disrupts intraneuronal microtubules and alters synaptic physiology. The destruction of normal cytoskeletal function is often a result of excessive free radial generation. The free radical-mediated changes result in loss of neuronal polarization and cells die of apoptosis leading to neurobehavioral disorders and dementia. Given that melatonin is an antioxidant, it has been tested for its efficacy in reducing damage to the cytoskeleton as well as limiting the behavioral effects. In this capacity melatonin has been found highly effective in reducing damage to essential cytoskeletal elements and improving neurobehavioral outcomes. Overall, melatonin may well find utility in reducing neural deterioration with age as well as improving the psychological well-being of individuals. Melatonin is an inexpensive non-toxic molecule which should be considered for use in a number of psychiatric diseases and circadian rhythm disorders.<hr/>La melatonina (N-acetil-5-metoxitriptamina) es una indolamina que produce la glándula pineal durante la noche. Se libera directamente en la circulación general con un ritmo circadiano. En las enfermedades psiquiátricas se presentan alteraciones en los ritmos biológicos. La melatonina es un cronobiótico ya que sincroniza los ritmos biológicos como el ciclo sueño-vigilia, el de la temperatura corporal y el ciclo de liberación de cortisol, con el fotoperiodo. Esta indolamina no actúa como un hipnótico clásico. Los efectos que ejerce sobre el sueño son acortar su latencia, prolongar el periodo de sueño natural y reducir los despertares nocturnos. Por lo anterior, se ha descrito como un compuesto que <<abre la puerta del sueño>>. En humanos se ha demostrado que produce una mejoría en la calidad de sueño en niños con patología neurológica, así como en pacientes con enfermedad de Alzheimer, en personas de edad avanzada con insomnio, en pacientes con esquizofrenia de larga evolución, depresión mayor y trastornos de ansiedad, etc. Otras características de la melatonina, importantes para la psiquiatría, es que esta molécula cruza la barrera hematoencefálica y actúa como un antioxidante. En 1993 se descubrió que la melatonina es un potente captador de radicales libres, que son moléculas que producen daño y muerte celular. La melatonina y los metabolitos que se generan cuando esta indolamina interacciona con las especies libres de oxígeno y de nitrógeno son eficaces en la eliminación de estas moléculas dañinas. Además, la melatonina activa las enzimas antioxidantes, incluidas la superóxido dismutasa, la glutatión peroxidasa, la glutatión reductasa y la catalasa, y facilita el transporte de electrones a través de la cadena respiratoria mitocondrial, con lo que reduce la pérdida neuronal por apoptosis. Las acciones antioxidantes de la melatonina han sido bien documentadas en modelos experimentales de las enfermedades de Alzheimer, Parkinson y Huntington. En el caso de la toxicidad que produce el péptido beta amiloide, por la generación de una gran cantidad de radicales libres, la melatonina previene la apoptosis, la lipoperoxidación, la formación de carbonilos y el daño al ADN. La melatonina mejora también algunos de los síntomas de la enfermedad de Alzheimer -como la agitación y la falta de sueño que se presentan al atardecer-, mejora el ciclo sueño-vigilia y disminuye el deterioro cognoscitivo y la atrofia bilateral grave de los lóbulos temporales. La pérdida de memoria que se produce en la enfermedad de Alzheimer también se presenta después del daño producido por el procedimiento de isquemia-reperfusión y, en la enfermedad de Parkinson, debido a una excesiva liberación de glutamato, que a su vez causa daño en las células piramidales por los radicales libres que se generan. La melatonina abate la pérdida de neuronas piramidales producida por el ácido kaínico, un agonista glutamatérgico, y preserva la memoria de los animales expuestos a daño por el procedimiento de isquemia-reperfusión. A la fecha no se conoce con exactitud con qué porcentaje colabora cada uno de los mecanismos de acción de la melatonina para proteger a las células del deterioro morfo-funcional. Sin embargo, es el antioxidante más potente descrito a la fecha e incrementa los niveles de enzimas antioxidantes a través de la estimulación de los receptores membranales. Las enfermedades neuropsiquiátricas se han considerado como enfermedades del citoesqueleto. Esto se sustenta en el hecho de que existe una pérdida de las conexiones sinápticas, que son estructuradas por el citoesqueleto, entre el hipocampo y la corteza prefrontal en el caso de la esquizofrenia, la depresión y el trastorno bipolar. En el caso de las demencias existe una organización aberrante del citoesqueleto en filamentos helicoidales apareados. En modelos experimentales de células en cultivo se han logrado reproducir condiciones moleculares semejantes a las que se presentan en las demencias y en la esquizofrenia. La melatonina previene el daño producido por los radicales libres sobre neurocitoesqueleto e inhibe la hiperfosforilación de la proteína tau, que cumple un papel crucial en la estabilización de los axones, en la formación de nuevas neuritas y, por lo tanto, en el establecimiento de las conexiones sinápticas. Además, los daños que producen los antipsicóticos sobre el citoesqueleto, con concentraciones semejantes a las que se alcanzan durante tratamientos prolongados, son revertidos y bloqueados por la melatonina. En conclusión, la información descrita en esta revisión indica que la melatonina puede ser útil en el tratamiento de las enfermedades neuropsiquiátricas ya que es un potente antioxidante, que protege a las neuronas y a las células de la glía de la muerte neuronal y protege al neurocitoesqueleto que determina la polaridad morfofuncional y el establecimiento de las conexiones sinápticas. Estas propiedades y la capacidad de la melatonina de cruzar la barrera hematoencefálica hacen que esta molécula sea un agente neuroprotector relevante en la psiquiatría. Sin embargo, es necesario realizar estudios clínicos controlados para determinar los efectos benéficos de la melatonina en las enfermedades neuropsiquiátricas. <![CDATA[<b>Trends of drug use 1998 to 2005 in three cities in the northern zone of Mexico</b>: <b>Ciudad Juarez</b><b>, </b><b>Monterrey</b><b> and </b><b>Tijuana</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0185-33252009000100003&lng=pt&nrm=iso&tlng=pt Drug use in Mexico has been on the rise since the 1970s. Nonetheless, this problem has exhibited important variations in the different regions of Mexico. To document these trends, the National Institute of Psychiatry Ramón de la Fuente (INP) has performed household surveys on addictions in different Mexican cities. In the 1970s and early 1980s surveys were conducted in the following cities: Mexico City, La Paz, Baja California Sur; Mexicali, Baja California Norte; Monterrey, Nuevo León; San Luis Potosí, San Luis Potosí; and Puebla, Puebla, among others. The first national survey in urban population was carried out in 1 988, and was repeated in 1993 and 1998, while the first national survey to included rural population was conducted in 2002, which is being followed by another study currently in the field. The student population has also been extensively studied, and has been included in three national drug surveys and studies performed in different entities. Antecedents Results from these surveys show that drug use has not increased in a uniform fashion throughout the Mexican Republic and both student and household surveys have demonstrated higher rates in the northwestern region of the country comprising the states of Baja California, Sonora and Chihuahua, which have exhibited above-average drug use on comparison with the remaining regions of the country. The most frequently consumed drug by the population is marihuana. The 1988 national household survey registered a rising prevalence in use of 2.9% in Mexican population aged 12-65 years of individuals who had used drugs at some time during their lifetime; in 1993 this prevalence increased to 3.32% and in 1998 to 4.70%; while in 2002 the percentage demonstrated a slight decrease to 3.48%. In 1988, the second place in drug preferences of the population was inhalants with a prevalence of drug use at some time during their lifetime of 0.76%; by 1993, the second place was occupied by cocaine. Prevalence of use of the latter was 0.33% in 1988; by 1993, cocaine increased to 0.56% and to 1.45% in 1998, presenting a slight decrease in use in 2002 (1.23%). From 1988-2002 non-prescribed medical drugs consumed were found in the third place in population preference. Objective This article compared drug use rates observed in three cities on or near Mexico's northern border with the U. S.: Ciudad Juarez, Chihuahua; Tijuana, Baja California Norte, and Monterrey, Nuevo León, were studied as part of the 1 998 national survey on addictions by selecting independent representative samples of these localities and with a new survey of these entities in 2005. Method The 1998 national survey of addictions was carried out in a representative sample of Mexican urban population (in localities of 2500 inhabitants). Independent samples were drawn from inhabitants living in several cities throughout Mexico. In this article we report the drug-use trends for three of these cities (Ciudad Juarez, Monterrey and Tijuana) by comparing the rates observed in 1998 with the results of a new wave of household surveys conducted in 2005 in the same cities using comparable methodology. Samples in both periods included population 12-65 years of age residing in households. Sample design was stratified by means of the following: several stages with localities (Áreas Geoestadísticas Básicas, AGEBS, its acronym in Spanish, census tracts); blocks of houses within the selected localities; segments of houses within sample blocks, and one individual per household as the selection unit in each stage. Sample size in Tijuana was 466 and 553 in 1998 and 2005, respectively, while sample sizes for Ciudad Juarez were 472 in 1998 and 606 in 2005, and for Monterrey this was 637 in 1998 and 675 in 2005, and the non-response rate was 23% in 1 998 and 20.3% in 2005. Instruments for obtaining information employed in both time frames considered were similar. Two types of questionnaires were administered: a household questionnaire that included sociodemographic information on all household inhabitants in the sample and their housing conditions and an standardized individual questionnaire administered in a face-to-face interview that collected information on the following: prevalence and use patterns of tobacco, alcohol, five types of illegal drugs (marihuana, cocaine, heroin, hallucinogens, amphetamine-type stimulants and other drugs); four types of medical pharmaceuticals utilized without a prescription (narcotics, stimulants, tranquilizers and sedatives), determining consequences and services utilization. In this article tobacco and alcohol use is not reported. This questionnaire has been extensively tested and used in previous surveys. Interviewers were persons academically prepared in the Social Sciences and trained in the logistics of the several survey stages and extensively supervised during field work. Results Highest rates of use were observed in Tijuana and Ciudad Juarez in contrast with Monterrey, which had lower rates. When use of any drug was considered, an increase in lifetime use from 1998-2005 was observed in all three cities; when use during the past year was contemplated, an increase was observed from 1998-2005 from 2.8-4.8% in the case of Ciudad Juarez and in Monterrey from 1.3%-2.0%, while these rates for Tijuana decreased from 5.4%-4.01%. Reports of use during the previous month fell in Tijuana from 4.4%-2.81 % and in Monterrey this decreased from 1.1 %-0.71 %, while in Ciudad Juarez drug use rates during the previous month increased from 2.4%-3.24%. It is important to mention that there was no statistical significance in any of the different prevalences types. Lifetime use of medical drugs without prescription increased in Tijuana and in Monterrey, while in Ciudad Juarez this remained stable from 1998-2005. In 2005, use of medical drugs decreased in Ciudad Juarez from 1.2%-0.88% and in Tijuana from 1.3%-1 .28%, while in Monterrey no use was detected in 1998, but 0.48% of interviewees did reported drug use in 2005. Previous-month use increased in Tijuana from 0.7%-1 .28% and in Monterrey this ranged from no use in 1998 to 0.48% by contrast in Ciudad Juarez previous-month drug use fell from 1.2-0.88%. In referring only to use of any illegal drug (excluding medical pharmaceutical), lifetime use increased in all three cities from 1998-2005; lifetime use doubled in Monterrey and Ciudad Juarez, while use during the previous year decreased in Tijuana from 4.4%-3.25% and increased in Ciudad Juarez from 1.6%-3.98% and in Monterrey from 1.3%-1 .52%. Prior-month increased in Ciudad Juarez from 1.2%-2.42%, while this exhibited a decrease in Tijuana from 3.9%-2.05% and in Monterrey from 1.1%-0.23%. Data also indicate that a high proportion of individuals in Monterrey have used only one drug; these percentages rose in the 1998-2005 period from 3.7%-8.96% numbers of the poly-drug users doubled in Tijuana from 4%-8.44% and in Ciudad Juarez from 3.2%-7.43%; in Tijuana this was due to an increase among males, and in Ciudad Juarez the number of poly-drug users increased in both genders.<hr/>El consumo de drogas en México ha ido en aumento. En la década de 1970, el Instituto Nacional de Psiquiatría realizó las primeras encuestas de hogares sobre el tema de las adicciones en población de distintas ciudades del país: la Ciudad de México, La Paz, B.C.S.; Mexicali, B.C.; Monterrey, N.L.; San Luis Potosí, S.L.P., y Puebla, Pue, entre otras y ha documentado las tendencias del problema y sus variaciones regionales. A nivel nacional se han realizado en hogares cuatro encuestas en 1988, en 1993, en 1998 y en 2002, denominadas <<Encuestas Nacionales de Adicciones>>. Asimismo se han levantado tres encuestas nacionales sobre drogas entre la población estudiantil, las cuales han dado cuenta de que el consumo de drogas no se ha incrementado de manera uniforme en el país, sino que tanto en las encuestas estudiantiles como entre las de adicciones ha resaltado la zona noroccidental, conformada por estados como Baja California, Sonora y Chihuahua, donde se tienen las mayores cifras de consumo de drogas en la República Mexicana. Las encuestas de adicciones indican que la droga que más ha consumido alguna vez en la vida la población urbana de 12 a 65 años es la mariguana, con los siguientes porcentajes: en 1988, 2.99%; en 1993, 3.32%; en 1998, 4.70%; y en la medición de 2002 disminuyó ligeramente a 3.48%. En 1988, el segundo lugar lo ocupaban los inhalables con 0.76%, pero en las demás mediciones ocupa este lugar la cocaína, con 0.56% en 1 993; 1.45% en 1998 y en 2002, 1.23%. En el tercer lugar se encuentran las drogas médicas consumidas sin prescripción desde 1988 hasta 2002. Este artículo presenta una comparación de las prevalencias de uso de drogas en tres ciudades de la Encuesta Nacional de Adicciones de 1998 con respecto a la Encuesta de ciudades de 2005 de las tres ciudades siguientes: Ciudad Juárez, Monterrey y Tijuana. La Encuesta Nacional de Adicciones de 1998 se realizó en una muestra representativa de la población urbana de todo el país (en localidades de más de 2500 habitantes). En esta encuesta, las 32 entidades del país se dividieron en tres regiones y también se obtuvieron muestras en ciudades fronterizas que fueron: Tijuana, Ciudad Juárez y Matamoros y en tres zonas metropolitanas que fueron: La ciudad de México, Guadalajara y Monterrey. La muestra fue de 12015 entrevistas completas. La encuesta de ciudades de 2005 se realizó en cuatro ciudades que fueron: Querétaro, Monterrey, Ciudad Juárez y Tijuana. Sin embargo, para efectos de este trabajo, solamente se comparan las tres últimas. Las dos encuestas tuvieron como objetivo a la población de 12 a 65 años de edad. En ambas se aplicaron dos cuestionarios: el de hogar con datos socioeconómicos y otro individual, cuyas secciones de consumo de drogas fueron iguales. El muestreo en ambas encuestas fue multietápico, probabilístico y estratificado, y en la última etapa se seleccionó a un individuo de cada hogar con un rango de edad de 12 a 65 años. Se obtuvo una no respuesta de 23% en 1998 y de 20.3% en 2005. <![CDATA[<b>The emotional response to music</b>: <b>attribution of emotions words to musical segments</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0185-33252009000100004&lng=pt&nrm=iso&tlng=pt Even though music is usually considered a source of intense, diverse, and specific affective states, at the present time there is not a standardized scientific procedure that reveals with reliable confidence the emotional processes and events evoked by music. The progress in understanding musical emotion crucially depends in the development of reasonable secure methods to record and analyze such a peculiar and universally-sought affective process. In 1936 Kate Hevner published a pioneer study where she used a list of 66 adjectives commonly used to categorize musical compositions arranged in a circle of eight groups of similar emotions. The volunteers selected the terms that seemed appropriate to categorize their emotional experience while they listened to masterpieces by Debussy, Mendelssohn, Paganini, Tchaikovsky, and Wagner. The results were presented in histograms showing a different profile for each piece. Subsequent studies have advanced in the methods and techniques to assess the emotions produced by music but there are many still unresolved difficulties concerning the criteria to choose the musical pieces, the terms of emotion, the design of the experiment, the proper controls, and the relevant statistical tools to analyze the results. The present study was undertaken in order to test and advance an experimental technique designed to evaluate and study the human emotions evoked by music. Specifically, the study intends to prove if different musical excerpts evoke a significant agreement in the selection of previously organized emotion terms within a relatively homogeneous population of human subjects. Since music constitutes a form of acoustic language that has been selected and developed through millennia of human cultural evolution for the expression and communication of emotional states, it is supposed that there will be a significant agreement in the attribution of terms of emotion to musical segments among human evaluators belonging to a relatively homogeneous population. The attribution system allowed both to obtain objective responses derived from introspection and to analyze the data by means of an appropriate statistical processing of data obtained in groups of subjects submitted to carefully selected musical stimuli. Volunteer subjects were 108 college-level students of both sexes with a mean age of 22 years from schools and universities located in the central Mexico. The audition and attribution sessions lasted for 90 min and were conducted in a specially adapted classroom located in each institution. Four criteria were established for the selection of the musical excerpts: instrumental music, homogeneous melody and musical theme, clear and distinct affective tone, and samples of different cultures. The ten selected pieces were: 1. Mozart's piano concerto no. 1 7, K 453, third movement; 2. A sound of the magnetic spectra of an aurora borealis, a natural event; 3. Mussorgsky's Gnome, from Pictures at an Exhibition orchestrated by Ravel; 4. Andean folk music; 5. Tchaikovsky's Fifth Symphony, second movement; 6. << Through the Never>>, heavy metal music by Metallica; 7. Japanese Usagi folk music played with koto and shyakuhachi; 8. Mahler's Fifth Symphony, second movement; 9. Taqsim Sigah, Arab folk music played with kamandja, and 1 0. Bach's Inventions in three parts for piano, BMW 797. The selected fragments and their replicas were divided in two to five musically homogeneous segments (mean segment duration: 24 seconds) and were played in different order in each occasion. The segments were played twice during the test. During the first audition, the complete piece was played in order for the subjects to become familiar with the composition and freely express their reaction in writing. During the second hearing, the same piece was played in the separate selected segments and the volunteers were asked to choose those emotion-referring terms that more accurately identified their music-evoked feelings from an adjunct chart obtained and arranged from an original list of 328 Spanish words designing particular emotions. The terms had been previously arranged in 28 sets of semantically related terms located in 14 bipolar axes of opposing affective polarity in a circumflex model of the affective system. The recorded attributions from all the subjects were captured and transformed into ranks. The non-parametric Friedman test of rank bifactorial variance for k related samples was selected for the statistical analysis of agreement. All the data were gathered in the 28 categories or sets of emotion obtained in the previous taxonomy of emotion terms and the difference among the musical segments was tested. The difference was significant for 24 of the 28 emotional categories for α=0.05 and 33 degrees of freedom (Fr ≥43.88). In order to establish in which segments were the main significant differences, the extension of the Friedman test for comparison of groups to a control was undertaken. Thus, after applying the appropriate formula, a critical value of the difference | R1 - Ru | was established at ≥18.59. In this way it was possible to plot the significance level of all 28 emotion categories for each music segment and thereby to obtain the emotion profile of each selected music fragment. The differences obtained for the musical pieces were established both for the significant response of individual emotion, groups of emotions, and the global profile of the response. In all the pieces used, one or more terms showed significance. Sometimes as many as seven terms appear predominant (Mahler, Mozart). In contrast other segments produce only one or two responses (aurora borealis, Arab music). In most musical segments there were null responses implying that there was an agreement concerning not only the emotions that were present, but also those that did not occur. Concerning the global response, there were several profiles recognizable among different pieces. The histogram is slanted to the left when positive and vigorous emotions are reported (Tchaikovsky, Bach). The predominance of emotions in the center-right sector corresponds to negative and quiet emotions (Arab music) or in the fourth sector of negative and agitated emotions (Mahler). Sometimes a <<U>> shaped profile was obtained when vigorous emotions predominated (Mahler, Metallica). A bell-shaped response was obtained when calm emotions were reported, both pleasant and unpleasant (Japanese music). There is also music that globally stimulates one of the four quadrants defined in the affective circle, such as pleasant (Mozart), unpleasant (Mussorgsky), exciting (Metallica) or relaxing emotions (Japanese music). The only segment that produced scattered responses in the four sectors of emotions was the aurora borealis. Very similar profiles were obtained with very different pieces, such as the identical responses to Mozart and Andean music. It is necessary to analyze the individual emotion terms to distinguish them. Several common characteristics can be detected in these two pieces, such as fast speed in tempo allegro, binary rhythm, counterpoint figures, and ascending melody, well known features in music composition. In contrast other segments evoked unpleasant responses (Mussorgsky), where fear, tension, doubt or pain was reported. The listener probably concedes a high value to a piece that evokes emotions that normally avoids in the context of a controlled artistic experience.<hr/>A pesar de que la música se considera habitualmente una fuente de estados afectivos variados diferentes e intensos, no existe una técnica en la ciencia que revele con suficiente fidelidad experimental los procesos y estados emocionales evocados por ella. Es así que el progreso en el entendimiento de la emoción musical depende críticamente del desarrollo de métodos razonablemente seguros para registrar y analizar este peculiar proceso afectivo. El presente estudio se realizó para desarrollar y probar una técnica diseñada para el estudio de las emociones humanas provocadas por la música. En particular se estudia si diferentes piezas musicales evocan un acuerdo significativo en la selección de términos de la emoción previamente sistematizados entre una población comparable de sujetos humanos. Dado que la música constituye un tipo de lenguaje acústico evolutiva y culturalmente seleccionado para la comunicación de estados emocionales, se puede suponer un acuerdo significativo entre evaluadores de una población homogénea en la atribución de términos de la emoción a segmentos musicales cuidadosamente seleccionados. El sistema de atribución elegido permitió obtener respuestas objetivas, derivadas de la introspección, a segmentos musicales y analizar los datos mediante un procesamiento estadístico apropiado de nivel de acuerdo entre observadores. Los voluntarios fueron 108 estudiantes con una edad promedio de 22 años, de ambos sexos, de cuatro escuelas de nivel superior en los Estados mexicanos de Querétaro y Guanajuato. Las sesiones duraron 90 minutos cada una y se realizaron en un salón adaptado en cada centro pedagógico. En las sesiones de audición y atribución se tocaron 10 obras musicales: cinco del repertorio clásico, cuatro del inventario popular propio y ajeno, así como la sonorización del espectro magnético de una aurora boreal, un fenómeno natural. Los fragmentos seleccionados, divididos en dos a cinco segmentos de 24seg de duración en promedio, se reprodujeron con diferente orden y en dos pasos consecutivos. Primero se tocó la sección completa para que el oyente expresara libremente sus reacciones por escrito. A continuación se tocaron los segmentos de la misma obra y el oyente escogió términos de la emoción que mejor identificaran su respuesta afectiva a cada uno de ellos a partir de un compendio adjunto. El formato de respuestas presentaba un arreglo donde el sujeto realizó la selección y atribución de los términos de la emoción que le evocaron los diferentes segmentos musicales al tiempo de escucharlos. Para esta tarea se proveyó a los sujetos de un esquema circular de términos de la emoción, anexo al formato, el cual se obtuvo a partir de una lista de 328 palabras en castellano que denominan emociones particulares. Los términos fueron agrupados finalmente en 28 conjuntos y 14 ejes de polaridades afectivas opuestas en un modelo circular del sistema afectivo, con un total de 168 términos. Para el análisis estadístico, las atribuciones de todos los sujetos participantes fueron transformadas a rangos y se aplicó la prueba no paramétrica de varianza bifactorial de Friedman para k muestras relacionadas como análisis de acuerdo entre observadores. Los datos se agruparon en las 28 categorías emocionales mencionadas y se probaron las diferencias entre los segmentos musicales. Éstas resultaron significativas en 24 de las 28 categorías emocionales para α = 0.05, con 33 grados de libertad (Fr ≥ 43.88). Para establecer en cuáles segmentos se ubicaban las diferencias, se aplicó la extensión de la prueba de Friedman para comparaciones de grupos con un control y se obtuvo un valor crítico de las diferencias, | R1 - Ru | ≥18.59, con lo cual fue posible graficar el nivel de significancia de todas las categorías emocionales para cada segmento musical. De esta forma se obtuvo el perfil emocional específico de cada fragmento de música para la población analizada. Los resultados muestran que en todos los segmentos musicales hay predominio significativo de una o más categorías de la emoción y que éstos son diferentes para la mayoría de los segmentos. Si, como es verosímil suponer, los términos de la emoción elegidos por los sujetos participantes correspondían efectivamente a estados emocionales particulares, entonces la mayoría de los segmentos musicales elegidos como estímulos parecen generar una respuesta emocional semejante y relativamente específica entre los escuchas, en función de las características de su composición. Esta técnica puede ser útil para generar y analizar estados emocionales específicos en situaciones experimentales y controladas de audición musical. <![CDATA[<b>Evaluation of a brief motivational intervention program for smokers</b>: <b>results of a pilot study</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0185-33252009000100005&lng=pt&nrm=iso&tlng=pt Tobacco consumption is a world-wide public health problem that has been associated with different types of cancer, cardiovascular and respiratory diseases, alterations in the reproductive system, dental problems and some eye diseases. In Mexico the National Survey of Addictions (2002) reported that 26.4% of the urban population between 12 and 65 years and 14.3% of the rural population are smokers. The Secretary of Health indicated that more than 53000 people died from diseases related to tobacco consumption. The consumption of tobacco stands among the ten first causes of morbidity and mortality in Mexico. In this sense, smoking is considered as one of the main public health problems in Mexico. Several organisms and institutions have undertaken actions in an attempt to solve it, such as the development of educative programs directed to the general population and programs to help smokers to quit this habit. Some of the main strategies to reduce cigarette consumption include nicotine replacement therapy, therapy not based on nicotine (antidepressants, some opiate antagonists and anxiolytic drugs), psychological programs, and the combination of some of them. Regarding psychological treatments, behavioral and cognitive behavioral techniques for smoking cessation hold empirical evidence about their efficacy for reducing the abuse of substances. In Mexico, psychological, nicotinic and non-nicotinic treatments to stop smoking are used. Nevertheless, the methodological and theoretical grounds of the psychological interventions are not well-established and there are no specific data about the changes in the consumption pattern after the application of the interventions and whether the effects of the treatment stay through the time. Specifically, the information about the efficacy of the brief interventions on smokers in the Mexican population is scarce. Although different studies have demonstrated that the brief motivational interventions are more effective to reduce the abuse of different substances than intensive interventions or no interventions at all, the techniques are not widely used in the treatment of tobacco consumption in Mexican population. With this evidence, the National Autonomous University of Mexico (UNAM) developed the Brief Motivational Intervention Program to treat smokers. The Brief Motivational Intervention is based in the Social Cognitive Theory, the Prevention of Relapses Model, in techniques of motivational interview and self-control techniques. Therefore, the goal of the present research is to evaluate a brief motivational intervention program for smokers. In order to achieve this aim, 10 individuals between 19 and 55 years old participated in the program; five individuals showed low nicotine dependence and five severe nicotine dependence according to the Questionnaire of Fagerström Tolerance. There was a public invitation and the participants consent to participate voluntarily in the <<Center of Psychological Services>> belonging to the Psychology Department, UNAM. The motivational brief intervention program for smokers consists of six sessions: an admission session, an evaluation session and four treatment sessions of one hour each. All of them were carried out individually based on the following theoretical and methodological components: social cognitive theory, techniques of motivational interview, techniques of self control and prevention of relapses model. The program was evaluated doing a comparison of the consumption pattern during and after the application of the brief intervention, and contrasting the level of self-efficacy before and after the application of the brief intervention. An analysis of variance (ANOVA) of repeated measures showed significant changes in the pattern of consumption (F [2, 18] =53.10,p<0.001), a Bonferroni post hoc test for binary comparisons indicated that the differences were between the baseline and treatment (p<0.001) and baseline and follow-up (p= 0.001). In relation to significant differences in the self-efficacy level, a Wilcoxon test showed differences in the following situations: disagreeable emotions (Z= 2.203, p<0.05), physical discomfort (Z = 2.492, p<0.05), conflict with others (Z= 2.556, p< 0.05) and pleasant moments with others (Z = 2.670, p<0.05). In all the cases, the level of self-efficacy reported in the second application increased as compared to the first. Results found in this research agree with those collected in other countries using brief intervention therapy, but specifically with the ones employed in Mexico with drinkers, users of cocaine and adolescents initiating drug consumption. This program makes special emphasis in the strengthening of self-efficacy and in the prevention of relapses model that maintains the change of the consumption behavior of the user during and after the intervention. However, users learn mainly to conceptualize a relapse as a part of the process to quit smoking and not as a failure or an addictive behavior that they will never be able to change. Carroll indicates that the essential principles of the cognitive behavioral programs for the treatment of addictive behaviors are that they allow for individualized programs and that the goals of the treatment reflect a collaborative process between the user and the therapist. These principles allow the user to stay in the program and motivate him/her to maintain a change in the addictive behavior. The brief intervention for smokers in this study has not only shown excellent effects in users with low dependency, but also with users with severe dependency to nicotine (according to the Questionnaire of Fagerström Tolerance). Even though they did not stop smoking completely, they diminished the consumption pattern and increased the number of days of abstinence. The previous finding is congruent with the assumptions of the harm reduction, which is considered as an alternative associated to a decrement on the real and the potential damage with the use of the drug, more than to trying to stop it. It is important to do a follow-up that shows a long-term maintenance of the behavior for at least 12 months after the treatment. Some biological markers (carbon monoxide in the expired air, levels of cotinine in tinkles or shapes) are also needed that will represent an objective measure that helps to increase the motivation with respect to the initial consumption during and after the intervention and also to verify the pattern of consumption reported by the users. This treatment for smokers it is an effective alternative for its adoption in institutions of health and must be a part of the preventive policies for the treatment of smokers in a national scope because it has an impact in the pattern of cigarette consumption and the associated organic damages.<hr/>El consumo de tabaco es un problema de salud pública en el mundo y se le ha asociado con diferentes tipos de cáncer, enfermedades cardiovasculares, enfermedades respiratorias, alteraciones en el sistema reproductivo, problemas dentales, úlcera péptica y algunas enfermedades de los ojos. De acuerdo con la Encuesta Nacional de Adicciones de 2002, en México fuman 26.4% de las personas entre 12 y 65 años de la población urbana y 14.3% de la población rural. En este sentido, la Secretaría de Salud señala que en México fallecen anualmente más de 53 mil personas por enfermedades relacionadas con el consumo de tabaco, lo que lo ubica entre los diez primeros lugares de morbilidad y mortalidad. Entre los tratamientos propuestos para dejar de fumar se identifican las terapias sustitutivas con nicotina, las terapias farmacológicas, los tratamientos psicológicos y combinaciones de ellos. En relación con los tratamientos psicológicos, existe evidencia empírica que muestra la efectividad de las técnicas conductuales y cognitivo-conductuales para dejar de fumar. En México, se emplean tratamientos psicológicos y farmacológicos (nicotínicos y no nicotínicos) en personas que desean dejar de fumar. Sin embargo, en dichas intervenciones no se reportan datos específicos de los cambios en el patrón de consumo después de la aplicación de dichas intervenciones y si éste se mantiene a lo largo del tiempo. Asimismo, se sabe específicamente poco de la efectividad de las intervenciones breves dirigidas a fumadores en la población mexicana. Por lo tanto, en la presente investigación se evalúa un programa de intervención breve motivacional para fumadores que incide en el patrón de consumo de cigarros, en la percepción de la autoeficacia de los usuarios al finalizar la aplicación del programa y en el seguimiento a los seis meses. Para cumplir con el propósito se aplicó el programa de intervención breve motivacional a 10 personas de entre 19 y 55 años de edad que deseaban dejar de fumar. La evaluación del programa se realizó a partir de la comparación del patrón de consumo antes, durante y después de la aplicación de la intervención breve, así como del nivel de autoeficacia antes y después de la aplicación de la intervención breve. Un análisis de varianza (ANOVA) de medidas repetidas mostró cambios significativos en el patrón de consumo entre la línea base, intervención y seguimiento (F[2,18]=53.10, p<0.001). Posteriormente se realizaron comparaciones binarias con el ajuste de Bonferroni, lo cual indicó que las diferencias se ubicaron sólo entre la línea base con respecto al tratamiento (p<0.001) y la línea base con respecto al seguimiento (p<=0.001). En relación con el nivel de autoeficacia se encontraron diferencias significativas antes y después de aplicar la prueba Wilcoxon, y así se obtuvieron diferencias significativas en las siguientes situaciones: emociones desagradables (Z= 2.203, p< 0.05), malestar físico (Z = 2.492, p<0.05), conflictos con otros (Z= 2.556, p<0.05) y momentos agradables con otros (Z= 2.670, p<0.05), en las que incrementó el nivel de autoeficacia reportada en la segunda aplicación con respecto a la primera. Los resultados obtenidos en esta investigación concuerdan con los observados en la aplicación de intervenciones breves en otros países, pero específicamente con los obtenidos en México con bebedores problema, usuarios de cocaína y adolescentes que se inician en el consumo de drogas. El programa de intervención breve motivacional enfatiza el fortalecimiento de la autoeficacia y el modelo de prevención de recaídas, que mantiene el cambio de la conducta de consumo del usuario durante y después de la intervención. El usuario aprende a conceptualizar la recaída como parte de un proceso de cambio y no como un fracaso o un comportamiento adictivo que nunca podrá cambiar. Por lo anterior, el tratamiento para fumadores es una alternativa efectiva para su adopción en instituciones de salud y debe formar parte de las políticas preventivas para el tratamiento de fumadores en el ámbito nacional, ya que tiene un impacto específico en el patrón de consumo de cigarrillos y, en esa medida, en los daños orgánicos asociados a su consumo. <![CDATA[<b>Profile of the relationship between psychological factors and hypoactive sexual desire in men and women</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0185-33252009000100006&lng=pt&nrm=iso&tlng=pt At the Department of Psychology of the Instituto Nacional de Perinatología 'Isidro Espinosa de los Reyes' (INPERIER), a hospital specialized in reproductive problems, we have detected a high proportion of couples with sexual problems. Therefore we decided to develope a line of research on human sexuality. Ever since, several exploratory studies have taken place with the aim of assessing the prevalence and the frequency of sexual dysfunction in both women and men attending the INPERIER. Our studies showed that 52% of women had one or more sexual dysfunctions and 38.8% of men had one or more sexual dysfunctions. Objective The main purpose of the study was to identify (in women and men) the relationship and the combination between hypoactive sexual desire disorder and some intervening variables catalogued as personality factors: gender role, self-esteem and locus of control. We also analysed sexual backgrounds by indentifying: child sexual traumatic experience, sexual information available, sex fears, masturbation and couple problems; in order to propose a profile of the relationship between psychological factors and hypoactive sexual desire in women and men. Material and methods A non-experimental, retrospective, transversal, field study with a correlation-multivariate design was used, which consisted of two independent samples divided into four groups selected through intentional sampling by quotas. This study is part of a larger research study aimed to assess risk factors for feminine and masculine sexual dysfunctions, whose original sample size was 400 participants. Out of this sample only participants with hypoactive sexual desire were selected, so in the end the groups included 58 women and 55 men. However, they were compared with the same number of participants with no sexual dysfunction. The groups were organized as follows: Group 1, women or men with no sexual dysfunction; Group 2, women or men who presented hypoactive sexual desire disorder. The participants included in the study were INPERIER regular patients. Samples were handled individually. In order to have an accurate sample all participants had to cover the selection criteria. Additionally, in order to place participants in the right group we used the Codified Clinical History Form on Female Sexuality (CCHFFS) for women -which also was used to examine their sexual background information- and in the case of men, we used the Male Sexuality Questionnaire. Furthermore the measurement of personality items was done by using the Inventory of Masculinity and Femininity IMAFE, the Coppersmith Self-Esteem Inventory and the Internal-External Locus of Control Scales. Sexuality questionnaires as well as other measurement instruments were applied at the External Clinic area during a single session followed by the transcription of data. In order to analyse the results we applied measures of central tendency to describe the socio-demographic factors (such as: age, civil status and education); for the analysis of personality factors (role of gender, self-esteem and locus of control) and its relationship with hypoactive sexual desire disorder we used the Student's T-test and estimated the Eta coefficient. The analysis of sexual background (child sexual traumatic experience, sexual information, sex fears, masturbation and couple problems) and its relationship with hypoactive sexual desire disorder was calculated by χ² and Cramer's V. Data analysis was performed with the statistical and data management package SPSS version 11. Results The thrown results showed that the descriptive analysis of data from women and men had a normal distribution. Also, results indicate that women with a hypoactive sexual desire disorder present a decrease in masculinity features and in their self-esteem level, and an increase in the submissive features when compared to women with no sexual dysfunction. When we analyzed the results of the sexual background in this group, we found a relationship between hypoactive sexual desire and child sexual traumatic experience, and between sex fears and couple problems, suggesting that these variables significantly intervene in the presence of hypoactive sexual desire disorder during women's adult life. In the discriminant analysis we obtained just one factor out of the six previously isolated variables with 75% of the cases correctly classified, indicating that this proportion of women with hypoactive sexual desire disorder are related to such indicators, the variables discriminated were an approximate explanation for the disorder. The results in the other group showed that in men with hypoactive sexual desire disorder there is a decrease in masculinity and femininity features and in the levels of self-esteem, plus an increase in the submissive features when compared to men with no sexual dysfunction. When we analyzed sexual background information, we found in the group with hypoactive sexual desire disorder that sex fears and couple problems significantly intervene in men's adult life. The discriminant analysis revealed a single factor with the six variables previously isolated, with 68.6% of cases correctly classified, which shows that men with hypoactive sexual desire disorder also have a relationship with the indicators, being the discriminated variables an approximate explanation. Conclusions When we discussed the results, we observed differences in two ways. First, for both women and men there was a decrease in masculinity features, defined as conducts directed to action, with well-defined, self-affirmed and self-reflective targets. Also there was a decrease in self-esteem, defined as the personal value judgment expressed as the individual's attitudes towards himself and the subjective experience transmitted to others; when masculinity features and self-esteem are diminished they may have an impact on sexuality, becoming a risk factor. In the group of men we also observed a decrease in the femininity features, defined as the traits aimed at feelings and abstraction, the expression of affection, the desire to provide protection as well as to experience nature feelings. When these three factors predominate they turn out to be a protective factor for an adequate practice of sexuality; both masculinity and femininity features could appear together or independently. In a second way, both in women and men we observed an increase in the submissive behavior, a risk indicator for the development of sexuality, because of the presence of self-denial, dependency, conformism, shyness and the capacity to endure suffering, features all shown as particular conducts. When it comes to sexual background in women, we found a close relationship with child sexual traumatic experience, sex fears and couple problems. In the case of men, the hypoactive sexual desire disorder was related to sex fears and couple problems. In this respect, in the review made by Basson, she mentions a new body of evidence that confirms what we have found in this study. She indicates that there are psychological factors that inhibit sexuality in women, for example, a history of child sexual traumatic experience may have a major impact in their sexual development, particularly in desire.<hr/>En el Departamento de Psicología del Instituto Nacional de Perinatología <<Isidro Espinosa de los Reyes>> (INPERIER), se detectó un alto porcentaje de parejas con problemas en su vida sexual. Por ello se abrió una línea de investigación en sexualidad humana, mediante la cual se han realizado estudios exploratorios para determinar la prevalencia y frecuencia de las disfunciones sexuales de la población atendida. Los resultados muestran que 52% de las mujeres estudiadas y 38.8% de los hombres estudiados presentaron una o más disfunciones sexuales. Objetivo El objetivo de este estudio es identificar la relación y la combinación, entre el deseo sexual hipoactivo y algunas variables catalogadas como factores de personalidad -el papel del género, la autoestima y el locus de control- y como antecedentes sexuales -experiencia sexual infantil traumática, información sexual, temores a la sexualidad, masturbación y problemas de pareja- con el fin de proponer un perfil de factores relacionados con el deseo sexual hipoactivo, tanto femenino como masculino. Material y método Se realizó un estudio no experimental de campo, retrospectivo y transversal, con un diseño correlacional-multivariado de dos muestras independientes divididas en cuatro grupos, seleccionados mediante un muestreo intencional por cuota. Este trabajo forma parte de una investigación más amplia sobre el estudio de algunos factores de riesgo en las disfunciones sexuales femeninas y masculinas, cuya muestra original constó de 400 participantes. De éstos sólo se tomaron los participantes con deseo sexual hipoactivo que fueron 58 mujeres y 55 hombres. Este grupo se comparó con el mismo número de participantes que no tuvieron ninguna disfunción sexual. Las muestras se clasificaron en dos grupos: como grupo 1 sin disfunciones sexuales y como grupo 2 con deseo sexual hipoactivo. Tanto el grupo de mujeres como el de hombres debieron cubrir todos los criterios de inclusión. Para la clasificación de los grupos y la captura de los antecedentes sexuales se utilizaron la Historia Clínica Codificada de la Sexualidad Femenina (HCCSF) y el Cuestionario de Sexualidad Versión Hombres. La medición de los factores de personalidad estudiados se realizó con el Inventario de Masculinidad y Feminidad IMAFE, el Inventario de Autoestima de Coopersmith, y la Escala de locus de control interno-externo. Primero se capturó la muestra de hombres y posteriormente la de mujeres. Resultados Los resultados obtenidos indican que las mujeres con deseo sexual hipoactivo presentan un decremento en las características de masculinidad y en los niveles de autoestima, y un incremento en las características de sumisión. Los resultados acerca de los antecedentes sexuales, en este grupo, mostraron que el deseo sexual hipoactivo se relaciona estrechamente con la experiencia sexual infantil traumática, los temores a la sexualidad y los problemas conyugales. En el análisis discriminante se obtuvo un solo factor por medio de las seis variables aisladas previamente, con el 75% de los casos correctamente clasificados. Los hombres con deseo sexual hipoactivo mostraron un decremento en las características de masculinidad y de feminidad, al igual que en los grados de autoestima, y un incremento en las características de sumisión. Los resultados que se obtuvieron acerca de los antecedentes sexuales mostraron que el deseo sexual hipoactivo tiene una relación estrecha con los temores a la sexualidad y los problemas conyugales. En el análisis discriminante se obtuvo un solo factor con las seis variables aisladas previamente, con el 68.6% de los casos correctamente clasificados. Conclusiones La investigación arrojó diferencias principalmente en dos sentidos. Por un lado tanto en las mujeres como en los hombres hay un decremento en las características de masculinidad y en la autoestima. Además, en los hombres también se presentó un decremento en los rasgos de feminidad. Este decremento muestra que estos tres factores constituyen indicadores de riesgo para el ejercicio satisfactorio de la sexualidad. Tanto las características de masculinidad como de feminidad pueden presentarse independientes o de manera combinada. <![CDATA[<b>Sex roles and mental health in a sample of the general Spanish population</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0185-33252009000100007&lng=pt&nrm=iso&tlng=pt Research on gender differences in health has generally shown that women report higher levels of minor psychiatric morbidity than men. One of the explicative variables for these findings is the different social roles of women and men. Sex role ideology refers to beliefs about appropriate roles for each gender, and is relevant from a psychological point of view because it is associated with self-definition, interactions between men and women and social relations. Most societies consider that women and men are different and consider that they should adopt different roles. These roles determine different social behaviors. Masculinity and femininity refer to feature differences, behaviours and interests assigned by society to each gender. The other two gender role categories proposed by Sandra Bem are androgyny (characterized by the presence of feminine and masculine characteristics) and an undifferentiated sex role (referring to individuals who have low levels of masculine or feminine characteristics). Classic theories on sex typing and gender role differences between women and men have suggested that such differences have been considered as normal and healthy, since they reflect social norms regarding appropriate behaviour in women and men. Furthermore, there is a tendency within mental health professionals who view masculine men and feminine women as normal and healthy. Nevertheless, research on this matter has not provided empirical evidence in relation to such hypotheses. It has also been suggested that reversing gender ideals can be stressful for men and women because such ideals are socially imposed, and therefore, obstruct self-regulation and are connected to the external representation of self-value. The aim of the current study is to find out whether there are mental health differences in a sample of the general Spanish population among the categories of sex role proposed by Sandra Bem. These categories are: masculine, which refers to individuals with high scores in masculinity and low scores in femininity; feminine, which comprises those individuals with high scores in femininity and low scores in masculinity; androgynous, which includes individuals with high scores in masculinity and femininity; and undifferentiated, which gathers those individuals with low scores in masculinity and femininity. The sample included 197 women and 140 men from the general population who voluntarily took part in the study. Participants ranged in age from 17 to 74 years, with a mean of 32.2 years (SD = 12.2), and with different social and demographic characteristics. They were assessed using the Bem Sex Role Inventory (BSRI), the Goldberg General Health Questionnaire (GHQ-28) and the Self-Esteem Inventory (SEQ). In order to know whether there were any statistically significant differences in health according to sex roles, and whether these interacted with gender, analysis of variance(ANOVA)and multivariate analysis of variance (MANOVA) were performed. The factors in all of them were the four sex role categories (androgynous, masculine, feminine and undifferentiated) and gender (men, women); and the dependent variables were the scores in GHQ-28 in the first group of analysis, and the two self-esteem factors in the second. In the MANOVA where the dependent variables were the four GHQ-28 scales of symptoms, we found that the interaction between sex roles and gender was statistically significant. When performing the analysis independently for each gender, we found that in the male sample there were statistically significant differences only according to sex roles in somatic symptoms. Men with undifferentiated sex roles showed fewer somatic symptoms than men with feminine or androgynous sex roles. In the female sample, we found statistically significant differences according to sex roles in somatic, anxiety and insomnia symptoms. Post hoc analysis with the Bonferroni adjustment showed that statistically significant differences occurred between the female groups with undifferentiated and androgynous sex roles. The latter female group showed fewer somatic, anxiety and insomnia symptoms. The analysis of the differences between women and men in mental health symptoms showed statistically significant differences in somatic, anxiety and insomnia symptoms. Women obtained higher average scores than men. However, there were no statistically significant differences in depressive symptoms nor social dysfunction. When the two factors from the self-esteem questionnaire were considered as dependent variables, the analyses of variance showed that the interaction between sex roles and gender was not statistically significant. Gender main effects were not statistically significant either, however sex role main effects were statistically significant. Post hoc analysis with the Bonferroni adjustment showed that individuals with an undifferentiated sex role evaluated themselves more negatively, and individuals with a masculine sex role evaluated themselves less negatively than those with a feminine sex role. There was no difference in self-confidence between individuals with androgynous sex roles and individuals with a masculine sex role, but both groups showed greater self-confidence than those individuals with feminine or undifferentiated sex roles. The latter group showed less self-confidence than individuals with a feminine sex role. These findings show that sex-typed individuals do not have better mental health or higher self-esteem than androgynous and undifferentiated individuals. Therefore, as in many other studies in other sociocultural settings, our results confirm the lack of empirical evidence for the traditional perspective that masculinity is better for men and femininity is better for women. Our data shows the complexity of relationships between sex roles and health, which depend on gender and on the kind of mental health indicator used. Therefore, while social dysfunction and depressive symptoms seem to be independent from sex role and gender, the effects of sex role on somatic, anxiety and insomnia symptoms were different for women and men. Whereas in the male sample, those with undifferentiated sex roles were the ones showing fewer somatic symptoms, in the women's sample, those with an androgynous sex role were the ones showing less somatic and anxiety and insomnia symptoms compared to those with an undifferentiated sex role. Nevertheless, self-esteem factors showed the highest differences between the various sex role categories. These factors seem to be the same for women and men. For example, we found that individuals with undifferentiated sex roles show higher negative self-worth and lower self-confidence than individuals classified in the other roles. In addition, individuals with a masculine sex role also value themselves less negatively and have higher self-confidence than individuals with a feminine sex role. Lastly, individuals classified in the androgynous sex role have similar self-confidence levels to those with a masculine sex role. The type of mental health symptoms where statistically significant. Differences between women and men are found, these differences were the same as those found in the female sample with regard to sex roles. This seems to indicate the relevance that sex roles have in mental health (in each gender), as some authors have highlighted. However, this study has some limitations to take into account when interpreting the results. Firstly, it is a transversal study, therefore we can talk about association, but not cause-and-effect relations between sex roles and health. Secondly, the sample is not random therefore it is not possible to generalize these results to the population.<hr/>Las investigaciones sobre las diferencias de género en salud mental generalmente muestran que los niveles de menor morbilidad psiquiátrica son mayores en las mujeres que en los hombres, siendo una de las variables explicativas de tales diferencias los roles sociales diferenciados en función del sexo. La ideología de los roles sexuales se refiere a las creencias respecto a qué roles son los adecuados para mujeres y hombres. Esto es relevante desde el punto de vista psicológico porque se asocia con la definición de sí-mismo, con las interacciones entre hombres y mujeres y con las relaciones sociales. La mayoría de las sociedades considera que mujeres y hombres son diferentes y deben ocupar roles distintos, por lo que los socializan de forma distinta. Y la masculinidad y la feminidad se refieren a las diferencias en rasgos, conductas e intereses que la sociedad ha asignado a cada uno de los géneros. Las teorías clásicas sobre las diferencias entre mujeres y hombres en roles de género y en tipificación sexual planteaban que tales diferencias eran normales y saludables, ya que reflejaban las normas sociales sobre la conducta apropiada para cada sexo. Además, los profesionales en salud mental tienden a ver a los hombres masculinos y a las mujeres femeninas como normales y sanas. Sin embargo, los resultados de las investigaciones no han aportado evidencia empírica de tales supuestos. Además, recientemente se ha reconocido que la inversión en los ideales de género puede ser estresante para hombres y mujeres porque se trata de ideales impuestos socialmente, dificultan la autorregulación y están relacionados con la representación externa de la autovalía. Pese a ello, la evidencia empírica no es concluyente, habiéndose realizado la mayoría de estudios sobre roles sexuales y salud con muestras anglosajonas, por lo que se desconoce si tal relación se da también en otras culturas. El objetivo del presente trabajo es conocer si existen diferencias en salud mental, en una muestra de la población general española, entre las cuatro opciones de rol sexual propuestas por Sandra Bem: masculinidad, feminidad, androginia e indiferenciación. La muestra estuvo formada por 337 personas de la población general que participaron voluntariamente en el estudio, sus edades oscilaron entre los 17 y 74 años (M = 32.2, SD = 12.2) y presentaron diferentes características sociodemográficas. Las muestras fueron evaluadas con el Bem Sex Role Inventory (BSRI), con el Cuestionario de salud general de Goldberg (GHQ-28) y con el Inventario de autoestima (Self-Esteem Inventory, SEQ). En los resultados encontramos que la asociación entre roles sexuales y salud mental depende del tipo de indicador de salud utilizado. Además, en la sintomatología somática, de ansiedad y de insomnio, también se encontró una relación estrecha con el género. En la muestra de hombres, los clasificados como indiferenciados presentaron menor sintomatología somática respecto a los clasificados como femeninos o como andróginos, mientras que en la muestra de mujeres las clasificadas como indiferenciadas fueron las que tuvieron más síntomas somáticos, de ansiedad e insomnio respecto a las andróginas. El análisis de las diferencias entre mujeres y hombres en sintomatología de salud mental mostró que se daban diferencias estadísticamente significativas en sintomatología somática, de ansiedad e insomnio, teniendo las mujeres puntuaciones medias más altas que los hombres. Sin embargo, no se obtuvieron diferencias estadísticamente significativas en sintomatología depresiva ni en disfunción social. Dichas diferencias coinciden con las obtenidas en la muestra de mujeres al analizar las diferencias en salud mental en función de los roles sexuales. Ello indica la relevancia que los roles sexuales pueden tener en las diferencias de género en salud mental, como han señalado algunos autores. Los resultados de este estudio muestran que el seguimiento de los roles sexuales tradicionales no conllevan a una mejor salud mental. En conclusión, como se ha encontrado en varios estudios realizados en otros entornos socio-culturales nuestros resultados confirman la falta de apoyo empírico para el modelo tradicional en el cual la masculinidad es mejor para los hombres y la feminidad para las mujeres. <![CDATA[<b>Frontal alpha activity in primary insomniacs with sleep onset difficulties</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0185-33252009000100008&lng=pt&nrm=iso&tlng=pt Difficulty in sleep initiation, with or without objective signs, is one of the most frequent complaints in primary insomniacs. The electroencephalographic (EEG) activity characteristic of waking (beta and alpha oscillations) is gradually replaced by the EEG signs of sleep (sleep spindles and theta/delta waves) during the sleep onset period (SOP) in normal subjects. The decrease in fast oscillations occurs at the first signs of stage 1, whereas theta and delta increase occurs later, indicating that waking promoting mechanisms are turned off before sleep-promoting mechanisms are fully started. It could be therefore hypothesized that difficulty in sleep initiation in insomniacs might be due to either a hyperactivation of waking promoting systems, a weakness of sleep promoting mechanisms or an imbalance between them. Quantitative EEG analysis has revealed higher beta during wakefulness, as well as during sleep and lower slow (delta) activity in insomniacs. The presence of alpha activity during cognitive information processing, especially of slow alpha activity in relation to attention, as well as in some pathologies associated to sleep disturbances, has suggested that alpha activity during sleep is a sign of activation; however, alpha activity during sleep has been less studied in insomniacs. Only broad bands have been considered in all of the aforementioned studies, and in almost all of them the analyses were restricted to central regions. It is therefore important to study the entire frequency spectrum of EEG activity in insomniacs. Sleep initiation does not occur simultaneously over the entire cortex but starts as a local process which gradually invades the rest of the cortex, in which the frontal lobes play a crucial role. Frontal and parietal regions are part of an important network involved in attention and conduction of thought. Thus, quantitative analysis of narrow EEG bands and their distribution in the cerebral cortex may contribute to a better understanding of neural mechanisms compromised in etiology of sleep initiation in primary insomnia. The main objective of the present investigation was, therefore, to analyze the spectral power of narrow EEG bands in the 19 derivations of the 10-20 International System during SOP in primary insomniacs with difficulty in sleep initiation. Given that one of the main complaints of insomniacs is the difficulty to initiate sleep and that hyperarousal is one of the factors proposed to be involved in the etiology of insomnia, EEG activity during SOP of the first night in the laboratory was analyzed to control activating effects of surrounding circumstances and isolate permanent EEG characteristics. Subjects were 19-34 years old, right-handed with primary sleep insomnia, which were thoroughly screened via structured psychiatric, medical and sleep interviews and scales. Subjects were younger and the age range was narrower than in other EEG frequency spectral content studies of primary insomniacs to avoid confounding effects of changes in sleep architecture or in EEG generated by development. All patients met the criteria for primary insomnia with sleep onset difficulty and impaired daytime function on three or more nights per week for at least six months and with no medical, psychiatric or neurological conditions; they were not medicated and had no other sleep disorders. Participants taking sleep medications or other drugs (urine test), respiratory or sleep disorders such as apnea and periodic limb movements (PSG) were excluded. The control group (n = 9) was matched for age and dexterity, but had no complaints of insomnia and reported their sleep as restorative and satisfactory. All participants underwent a single night of standard polysomnography (EEG, EOG and EMG) in the laboratory. In addition, the 19 electrode sites of the 10-20 International System referred to ipsilateral earlobes, oral-nasal airflow and anterior tibialis EMG were recorded. PSG was scored in 30 sec epochs, blind to the subject group according to Rechtschaffen and Kales criteria. EEG from SOP (lights out to consolidate sleep), defined as 3 consecutive minutes of delta sleep, was digitized at 1024 Hz with 12 bits resolution and filter settings of 0.03-70 Hz. EEG was segmented into two-sec non-overlapping epochs and inspected for artifacts. All artifact-free epochs were Fast Fourier Transformed and absolute (AP) and relative power (RP: AP in each Hz bin/total spectrum power × 100) was obtained for 1 Hz bins. AP and RP was log-transformed before statistical analysis, and was averaged over each derivation and sleep stage of SOP. Group differences were compared by means of Student's t tests and probability level was set at p<0.05. In contrast with healthy controls, insomniac patients exhibited higher alpha RP (7 and 8 Hz) over all frontal derivations during stage 2 of SOP and higher RP of isolated beta and gamma frequencies during wakefulness. PSG of both groups showed the <<first night effect>> with decreased total sleep time, decreased sleep efficiency index and REM sleep percentage compared to normal values for the 20-30 age decade; PSG variables were not significantly different between the two groups except for wakefulness percentage during SOP. Insomniacs did differ from controls in subjective estimation of sleep quality and continuity in spite of similar PSG. The absence of significant differences between insomniacs and controls in sleep EEG activity (delta, theta and sigma frequencies) suggests that sleep homeostatic function is preserved in insomniacs, which agrees with results obtained in other studies after partial sleep deprivation. The absence of a stronger promoting effect of insomnia in the insomniac group by the first recording night indicates that EEG characteristics found in this group cannot be attributed to external stimuli nor surrounding circumstances and rather suggests a more stable alteration; however, further studies of larger groups and other age spans are needed to confirm present results. The evidence mentioned above suggests an imbalance between waking and sleep promoting mechanisms in primary insomniacs with difficulty in sleep initiation and sleep perception. Attention depends not only on vigilance level, but also on frontal regions which, together with posterior association areas, conform an essential network for purposive endogenously guided attention. The presence in insomniacs of alpha activity in frontal regions, which is a sign of top-down control of attention, and its absence in posterior regions during stage 2 suggests the persistence of a certain level of endogenous attention during stage 2 of SOP, which contributes in turn to the subjective perception of sleep onset difficulties and bad sleep quality.<hr/>La dificultad para conciliar el sueño es uno de los síntomas más frecuentes del insomnio primario. La apreciación subjetiva de un periodo prolongado de latencia al sueño, aun en presencia de signos de sueño, puede deberse a la coexistencia de los mecanismos promotores de la vigilia y del sueño, y la lucha por el predominio de uno de ellos. La red de atención ejecutiva, conformada por las áreas de asociación frontales y parietales, cumple un papel de particular importancia en el control endógeno de la atención y en la regulación del alertamiento por parte de la corteza. Las frecuencias del EEG en el rango de actividad alfa lenta (7 y 8 Hz) participan en los procesos cognoscitivos activos de la vigilia, especialmente en la atención y la memoria, y son indicadoras del control corticofugo, o top-down, de estos procesos. Sin embargo, el análisis cuantitativo del EEG durante el proceso de conciliación del sueño en los insomnes se ha centrado fundamentalmente en la actividad delta, theta y beta, y únicamente en las regiones centrales (C3 y C4), de tal forma que el análisis de banda estrecha del EEG y su distribución en toda la corteza podría contribuir a una mejor comprensión de los mecanismos neurales comprometidos en la etiología del insomnio primario. El objetivo principal de esta investigación es, por lo tanto, analizar el espectro de frecuencias con resolución de 1 Hz en todas las derivaciones del Sistema Internacional 10-20 en insomnes primarios crónicos durante el periodo inicial del sueño (PIS) y comparar a estos últimos con un grupo control. Con el fin de aislar las características del EEG de los insomnes de causas circunstanciales, se analizará la primera noche de PSG igualando en ambos grupos el efecto activador que ejerce el medio circundante sobre el Sistema Nervioso Central, el estado psicológico y la arquitectura del sueño. Se estudiaron nueve pacientes insomnes primarios cuya queja principal era la dificultad para iniciar el sueño y nueve sujetos controles libres de problemas de sueño, diestros y entre 19-34 años de edad. Se realizó la PSG durante la primera noche en el laboratorio siguiendo los procedimientos estándar y adicionalmente se registraron las 19 derivaciones del Sistema Internacional 10-20. Se obtuvieron los espectros de potencia del EEG de todas las derivaciones con resolución de 1 Hz del PIS (tiempo comprendido entre las buenas noches y el sueño consolidado: 3 minutos consecutivos de sueño delta). Los insomnes tuvieron mayor actividad alfa lenta (7 y 8 Hz) en las regiones frontales durante la etapa 2 del PIS y de algunas frecuencias rápidas (beta y gamma) en la vigilia; subestimaron la calidad de sueño; y mostraron el mismo efecto de primera noche que los controles. La ausencia de diferencias entre los dos grupos en el EEG típico del sueño (delta, theta y sigma) sugiere que los insomnes tienen preservada la función homeostásica del sueño. La ausencia de diferencias en la PSG de los insomnes y controles indica que la dificultad para conciliar el sueño del grupo de insomnes no se encuentra en estímulos externos ambientales ni en condiciones circunstanciales y sugiere que se debe a alteraciones más permanentes. El conjunto de estas evidencias apunta hacia una alteración de la vigilia en concordancia con las hipótesis que proponen que el insomnio tiene un componente primordial de activación fisiológica y psicológica. La atención depende, además del nivel de vigilancia, de las regiones frontales que, junto con las áreas posteriores de asociación, conforman una red esencial para la atención dirigida endogenamente. La presencia de ritmo alfa en las regiones frontales y su ausencia en las áreas posteriores durante la etapa 2 en los insomnes podría reflejar la permanencia de cierto nivel de atención endógena durante la etapa 2 del PIS y podría constituir un mecanismo alterado del sistema frontal subyacente a la dificultad para iniciar el sueño. <![CDATA[<b>Internal desynchrony as promotor of disease and behavioral disturbance</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0185-33252009000100009&lng=pt&nrm=iso&tlng=pt Life on our planet is ruled by a temporary structure that governs our activities, our days and our calendars. In order to cope with a daily changing environment, organisms have developed adaptive strategies by exhibiting daily behavioral and physiological changes. Biological rhythms are properties conserved in all the levels of organization, from unicellular to prokaryotes to upper plants and mammals. A biological rhythm is defined as the recurrence of a biological phenomenon in regular intervals of time. Biological rhythms in behaviour and physiology are controled by an internal clock which synchronizes its oscillations to external time cues that have the capacity to adjust the clock's mechanism and keep it coupled to external fluctuations. The suprachiasmatic nucleus (SCN) of the hypothalamus in mammals is the master circadian clock which is mainly entrained by the light-dark cycle. The SCN transmits time signals to the brain and then to the whole body and by means of its time signals the SCN keeps a temporal order in diverse oscillations of the body and adjusted to the light-dark cycle. The correct temporal order enables an individual to adequate functioning in harmony with the external cycles. Biological rhythms have a hereditary character, thus its expression is genetically determined. All animals, plants, and probably all organism show some type of physiological rhythmic variation (metabolic rate, production of heat, flowering, etc.) that allow for the adaptation to a rhythmic environment. Biological rhythms enable individuals to anticipate and to be prepared to the demands of the prominent cyclic environmental changes, which are necessary for survival. Also, biological rhythms promote showing maximum levels of a physiological variable at the right moment when the environment requires a maximal response. In humans, an example of circadian rhythms is the sleep-wake cycle; simultaneously, a series of physiological changes are exhibited, also with circadian characteristics (close to 24 hours). Circadian oscillations are observed in the liberation of luteinizant hormone, in plasma cortisol, leptin, insulin, glucose and growth hormone just to mentions some examples. The SCN controls circadian rhythmicity via projections to the autonomic system and by controlling the hypothalamus-adenohipofisis-adrenal axis. In this way, the SCN transmits phase and period to the peripheral oscillators to maintain an internal synchrony. Modern life favors situations that oppose the time signals in the environment and promote conflicting signals to the SCN and its effectors. The consequence is that circadian oscillators uncouple from the master clock and from the external cycles leading to oscillations out of synchrony with the environment, which is known as internal desynchronization. The consequence is that physiological variables reach their peak expression at wrong moments according to environmental demands leading then to deficient responses and to disease in the long run. Also, levels of attention, learning and memory reach peak expression at wrong moments of the day leading individuals to exhibit a deficient performance at school or work. The disturbed sleep patterns promote fatigue and irritability, which difficult social interaction. Internal desynchronization results from transmeridional traveling for which people pass multiple hourly regions. This results in an abrupt change in the time schedule and a syndrome known as <<jet lag>>. Frequent travelers complain about difficulties to adjust their sleep-wake cycle to the new schedule, thus resulting in fatigue, increased sleepiness and reduced attention. Jet lag results from a loss of synchrony among biological rhythms and among diverse functions, which remain out of phase with the day-night cycle. This <<internal desynchrony>> is the cause of general discomfort, decrement in the physical and mental performance, as well as irritability and depression. Frequently, gastrointestinal disorders are a by-product of food consumption at an unusual schedule. The state of internal desynchrony is transitory and depends on the number of time zones that were crossed; thus, adaptation to a new external cycle can take from four to seven days. Another example of internal desynchrony is observed in individuals exposed to work shifts or to nocturnal work schedules (night work). In such conditions, circadian fluctuations in behavioral, hormonal and metabolic parameters are observed but their temporary relation with the external cycles is modified. The internal synchrony is thus affected by troubled environmental signs, out of phase with the daily activities of the individual; among them are the hours of food intake, the exposure to light during resting hours, the low temperature of the night, and the forced activity when homeostatic processes indicate a need to rest. This internal desynchrony leads to gastrointestinal disorders, disturbed metabolic fluctuations, disturbed cardiovascular functions, altered menstrual cycle, sleep disorders, sleepiness, increase of work accidents, etc. Internal desynchrony is especially due to the fact that circadian fluctuations are influenced by daily external cycles, but also by homeostatic factors, and can suffer from additional disturbance by sleep deprivation. Despite years of night work experience, incapacity to adapt to night work may persist. Only a minority of shift workers achieve spontaneous adjustment of the rhythms of core body temperature, melatonin, cortisol, thyroid stimulating hormone, or prolactin secretion to shifts by nocturnal work. Therefore shift and night workers develop a propensity to smoke, drink alcoholic beverages and use stimulant products. After five years of shift or night work, health problems appear with a higher incidence than in the general population. The growing social demand of shift work makes it necessary to decide on the characteristics and forms of shifts to carry out, and up to now organizing such working schedules remaing a serious problem. The improvement of health services has increased life expectancies and thus the general population is becoming old and people survive more years. Older people ail from health and behavioral problems including a deterioration of the biological rhythms. Main alterations consist of a loss of expression of the circadian functions or a decrease of the amplitude of the rhythms, and instability of synchronization mechanisms day by day. All in all, this implies a decreased capacity of the clock to adjust to the solar day. The decreased efficacy of the aging biological clock is evident in the fragmented sleep patterns and the disturbed sleep/wake rhythms, characterized by short sleep episodes during the day and decreased sleep during the night. Some studies suggest that the disturbed circadian rhythms may be the cause of diverse diseases associated with the elderly. In conclusion, during the last 100 years we have changed our lifestyle so radically that we lack already a physiological design to adapt so quickly to modernity. We can state that our body is designed for a world that does not exist. In this article we present a review of the main alterations of the biological rhythms generated by the transmeridional trips, shift-work and aging, their behavioral and physiological consequences that lead to disease and poor mental performance. We also discuss possible strategies that need to be explored and that may help people to improve their quality of life and to prevent internal desynchrony.<hr/>La vida se rige por una estructura temporal que gobierna nuestras horas, nuestros días y nuestros calendarios. Como parte de la adaptación a los ciclos de tiempo que impone el planeta, todo organismo presenta ritmos en su actividad y fisiología. Los ritmos biológicos son una propiedad conservada en todos los niveles de organización, desde organismos unicelulares procariontes hasta plantas superiores y mamíferos. De ellos, los más sólidos son aquellos asociados a los ciclos externos por la alternancia del día y la noche y por la alternancia de las estaciones del año. Los ritmos biológicos fisiológicos y conductuales son procesos dependientes de un reloj interno capaz de ajustar sus oscilaciones a claves de tiempo externas que lo mantienen sincronizado a estas fluctuaciones externas. El núcleo supraquiasmático del hipotálamo (NSQ) es en los mamíferos el principal reloj circadiano y se sincroniza principalmente por el ciclo luz-oscuridad. El NSQ transmite señales de tiempo al cerebro y de ahí al resto del organismo, y por medio de estas señales de tiempo mantiene un orden temporal en diversas funciones del cuerpo y las mantiene ajustadas al ciclo luz-oscuridad. El correcto orden temporal interno permite un adecuado funcionamiento del individuo en armonía con el medio externo y le permite exhibir respuestas adecuadas a un ambiente cambiante y predecible. El estilo de vida del hombre moderno propicia situaciones que llevan a alteraciones de nuestros ritmos biológicos que causan una desadaptación temporal, que a su vez redunda en daños a la salud, ya que afecta tanto la fisiología como la forma en que organizamos nuestra conducta. Un ejemplo de ello son los viajes a través de múltiples regiones horarias. Estos cambios de horario bruscos provocan un síndrome conocido como jet-lag, que consiste en un conflicto transitorio entre el tiempo <<interno>> y el tiempo <<externo>>, lo cual se denomina <<desincronización interna>>. El jet-lag se define como un conjunto de síntomas causados por una alteración del patrón de sueño, y de la expresión de ritmos biológicos fuera de fase entre sí y fuera de fase con el ciclo del día y la noche. Esta es la causa del malestar general, el deterioro del desempeño mental y físico, así como de la irritabilidad y depresión. Son frecuentes también las alteraciones gastrointestinales, resultado del consumo de alimento en un horario inusual. Otro ejemplo de alteraciones en los ritmos circadianos se observa en los trabajadores con turnos rotatorios o en turnos nocturnos. En estas condiciones se produce un conflicto entre las señales temporales asociadas al ciclo diurno y que transmite el reloj con las actividades y alimentos del trabajador en turnos. De este esquema de trabajo resulta una reducción de las horas de sueño y una alteración de los ritmos circadianos, que llevan a una desincronización interna. Ésta, al igual que en el caso del jet-lag, redunda en un deterioro de las funciones mentales y de la capacidad de atención y memorización, que se asocian a irritabilidad y problemas emocionales. Además, se observan consecuencias en la salud con incremento en la incidencia de malestares gastrointestinales, enfermedades cardiovasculares, obesidad y diabetes. La mejoría en los servicios de salud ha incrementado las expectativas de vida, lo que entonces enfrenta a la humanidad a una población que logra sobrevivir muchos años de su vejez con los cambios de conducta y salud propios de su edad, entre los que se incluye un deterioro de los ritmos biológicos. En este trabajo presentamos una revisión de las principales alteraciones de los ritmos biológicos generadas por los viajes transmeridionales, la vejez y el trabajo en turnos. También discutimos la relevancia de una buena adaptación de los ritmos biológicos y las consecuencias conductuales y fisiológicas que por su alteración llevan a la enfermedad y a un desempeño mental deficiente. También sugerimos estrategias que necesitan ser exploradas y que podrían ayudar prevenir la desincronización interna para mejorar la calidad de vida. <![CDATA[<b>In Memoriam Javier Mariátegui Chiappe</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0185-33252009000100010&lng=pt&nrm=iso&tlng=pt Life on our planet is ruled by a temporary structure that governs our activities, our days and our calendars. In order to cope with a daily changing environment, organisms have developed adaptive strategies by exhibiting daily behavioral and physiological changes. Biological rhythms are properties conserved in all the levels of organization, from unicellular to prokaryotes to upper plants and mammals. A biological rhythm is defined as the recurrence of a biological phenomenon in regular intervals of time. Biological rhythms in behaviour and physiology are controled by an internal clock which synchronizes its oscillations to external time cues that have the capacity to adjust the clock's mechanism and keep it coupled to external fluctuations. The suprachiasmatic nucleus (SCN) of the hypothalamus in mammals is the master circadian clock which is mainly entrained by the light-dark cycle. The SCN transmits time signals to the brain and then to the whole body and by means of its time signals the SCN keeps a temporal order in diverse oscillations of the body and adjusted to the light-dark cycle. The correct temporal order enables an individual to adequate functioning in harmony with the external cycles. Biological rhythms have a hereditary character, thus its expression is genetically determined. All animals, plants, and probably all organism show some type of physiological rhythmic variation (metabolic rate, production of heat, flowering, etc.) that allow for the adaptation to a rhythmic environment. Biological rhythms enable individuals to anticipate and to be prepared to the demands of the prominent cyclic environmental changes, which are necessary for survival. Also, biological rhythms promote showing maximum levels of a physiological variable at the right moment when the environment requires a maximal response. In humans, an example of circadian rhythms is the sleep-wake cycle; simultaneously, a series of physiological changes are exhibited, also with circadian characteristics (close to 24 hours). Circadian oscillations are observed in the liberation of luteinizant hormone, in plasma cortisol, leptin, insulin, glucose and growth hormone just to mentions some examples. The SCN controls circadian rhythmicity via projections to the autonomic system and by controlling the hypothalamus-adenohipofisis-adrenal axis. In this way, the SCN transmits phase and period to the peripheral oscillators to maintain an internal synchrony. Modern life favors situations that oppose the time signals in the environment and promote conflicting signals to the SCN and its effectors. The consequence is that circadian oscillators uncouple from the master clock and from the external cycles leading to oscillations out of synchrony with the environment, which is known as internal desynchronization. The consequence is that physiological variables reach their peak expression at wrong moments according to environmental demands leading then to deficient responses and to disease in the long run. Also, levels of attention, learning and memory reach peak expression at wrong moments of the day leading individuals to exhibit a deficient performance at school or work. The disturbed sleep patterns promote fatigue and irritability, which difficult social interaction. Internal desynchronization results from transmeridional traveling for which people pass multiple hourly regions. This results in an abrupt change in the time schedule and a syndrome known as <<jet lag>>. Frequent travelers complain about difficulties to adjust their sleep-wake cycle to the new schedule, thus resulting in fatigue, increased sleepiness and reduced attention. Jet lag results from a loss of synchrony among biological rhythms and among diverse functions, which remain out of phase with the day-night cycle. This <<internal desynchrony>> is the cause of general discomfort, decrement in the physical and mental performance, as well as irritability and depression. Frequently, gastrointestinal disorders are a by-product of food consumption at an unusual schedule. The state of internal desynchrony is transitory and depends on the number of time zones that were crossed; thus, adaptation to a new external cycle can take from four to seven days. Another example of internal desynchrony is observed in individuals exposed to work shifts or to nocturnal work schedules (night work). In such conditions, circadian fluctuations in behavioral, hormonal and metabolic parameters are observed but their temporary relation with the external cycles is modified. The internal synchrony is thus affected by troubled environmental signs, out of phase with the daily activities of the individual; among them are the hours of food intake, the exposure to light during resting hours, the low temperature of the night, and the forced activity when homeostatic processes indicate a need to rest. This internal desynchrony leads to gastrointestinal disorders, disturbed metabolic fluctuations, disturbed cardiovascular functions, altered menstrual cycle, sleep disorders, sleepiness, increase of work accidents, etc. Internal desynchrony is especially due to the fact that circadian fluctuations are influenced by daily external cycles, but also by homeostatic factors, and can suffer from additional disturbance by sleep deprivation. Despite years of night work experience, incapacity to adapt to night work may persist. Only a minority of shift workers achieve spontaneous adjustment of the rhythms of core body temperature, melatonin, cortisol, thyroid stimulating hormone, or prolactin secretion to shifts by nocturnal work. Therefore shift and night workers develop a propensity to smoke, drink alcoholic beverages and use stimulant products. After five years of shift or night work, health problems appear with a higher incidence than in the general population. The growing social demand of shift work makes it necessary to decide on the characteristics and forms of shifts to carry out, and up to now organizing such working schedules remaing a serious problem. The improvement of health services has increased life expectancies and thus the general population is becoming old and people survive more years. Older people ail from health and behavioral problems including a deterioration of the biological rhythms. Main alterations consist of a loss of expression of the circadian functions or a decrease of the amplitude of the rhythms, and instability of synchronization mechanisms day by day. All in all, this implies a decreased capacity of the clock to adjust to the solar day. The decreased efficacy of the aging biological clock is evident in the fragmented sleep patterns and the disturbed sleep/wake rhythms, characterized by short sleep episodes during the day and decreased sleep during the night. Some studies suggest that the disturbed circadian rhythms may be the cause of diverse diseases associated with the elderly. In conclusion, during the last 100 years we have changed our lifestyle so radically that we lack already a physiological design to adapt so quickly to modernity. We can state that our body is designed for a world that does not exist. In this article we present a review of the main alterations of the biological rhythms generated by the transmeridional trips, shift-work and aging, their behavioral and physiological consequences that lead to disease and poor mental performance. We also discuss possible strategies that need to be explored and that may help people to improve their quality of life and to prevent internal desynchrony.<hr/>La vida se rige por una estructura temporal que gobierna nuestras horas, nuestros días y nuestros calendarios. Como parte de la adaptación a los ciclos de tiempo que impone el planeta, todo organismo presenta ritmos en su actividad y fisiología. Los ritmos biológicos son una propiedad conservada en todos los niveles de organización, desde organismos unicelulares procariontes hasta plantas superiores y mamíferos. De ellos, los más sólidos son aquellos asociados a los ciclos externos por la alternancia del día y la noche y por la alternancia de las estaciones del año. Los ritmos biológicos fisiológicos y conductuales son procesos dependientes de un reloj interno capaz de ajustar sus oscilaciones a claves de tiempo externas que lo mantienen sincronizado a estas fluctuaciones externas. El núcleo supraquiasmático del hipotálamo (NSQ) es en los mamíferos el principal reloj circadiano y se sincroniza principalmente por el ciclo luz-oscuridad. El NSQ transmite señales de tiempo al cerebro y de ahí al resto del organismo, y por medio de estas señales de tiempo mantiene un orden temporal en diversas funciones del cuerpo y las mantiene ajustadas al ciclo luz-oscuridad. El correcto orden temporal interno permite un adecuado funcionamiento del individuo en armonía con el medio externo y le permite exhibir respuestas adecuadas a un ambiente cambiante y predecible. El estilo de vida del hombre moderno propicia situaciones que llevan a alteraciones de nuestros ritmos biológicos que causan una desadaptación temporal, que a su vez redunda en daños a la salud, ya que afecta tanto la fisiología como la forma en que organizamos nuestra conducta. Un ejemplo de ello son los viajes a través de múltiples regiones horarias. Estos cambios de horario bruscos provocan un síndrome conocido como jet-lag, que consiste en un conflicto transitorio entre el tiempo <<interno>> y el tiempo <<externo>>, lo cual se denomina <<desincronización interna>>. El jet-lag se define como un conjunto de síntomas causados por una alteración del patrón de sueño, y de la expresión de ritmos biológicos fuera de fase entre sí y fuera de fase con el ciclo del día y la noche. Esta es la causa del malestar general, el deterioro del desempeño mental y físico, así como de la irritabilidad y depresión. Son frecuentes también las alteraciones gastrointestinales, resultado del consumo de alimento en un horario inusual. Otro ejemplo de alteraciones en los ritmos circadianos se observa en los trabajadores con turnos rotatorios o en turnos nocturnos. En estas condiciones se produce un conflicto entre las señales temporales asociadas al ciclo diurno y que transmite el reloj con las actividades y alimentos del trabajador en turnos. De este esquema de trabajo resulta una reducción de las horas de sueño y una alteración de los ritmos circadianos, que llevan a una desincronización interna. Ésta, al igual que en el caso del jet-lag, redunda en un deterioro de las funciones mentales y de la capacidad de atención y memorización, que se asocian a irritabilidad y problemas emocionales. Además, se observan consecuencias en la salud con incremento en la incidencia de malestares gastrointestinales, enfermedades cardiovasculares, obesidad y diabetes. La mejoría en los servicios de salud ha incrementado las expectativas de vida, lo que entonces enfrenta a la humanidad a una población que logra sobrevivir muchos años de su vejez con los cambios de conducta y salud propios de su edad, entre los que se incluye un deterioro de los ritmos biológicos. En este trabajo presentamos una revisión de las principales alteraciones de los ritmos biológicos generadas por los viajes transmeridionales, la vejez y el trabajo en turnos. También discutimos la relevancia de una buena adaptación de los ritmos biológicos y las consecuencias conductuales y fisiológicas que por su alteración llevan a la enfermedad y a un desempeño mental deficiente. También sugerimos estrategias que necesitan ser exploradas y que podrían ayudar prevenir la desincronización interna para mejorar la calidad de vida. <![CDATA[<b>Obesity and metabolic syndrome as public health problems: A reflection. </b><b>Second part</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0185-33252009000100011&lng=pt&nrm=iso&tlng=pt Life on our planet is ruled by a temporary structure that governs our activities, our days and our calendars. In order to cope with a daily changing environment, organisms have developed adaptive strategies by exhibiting daily behavioral and physiological changes. Biological rhythms are properties conserved in all the levels of organization, from unicellular to prokaryotes to upper plants and mammals. A biological rhythm is defined as the recurrence of a biological phenomenon in regular intervals of time. Biological rhythms in behaviour and physiology are controled by an internal clock which synchronizes its oscillations to external time cues that have the capacity to adjust the clock's mechanism and keep it coupled to external fluctuations. The suprachiasmatic nucleus (SCN) of the hypothalamus in mammals is the master circadian clock which is mainly entrained by the light-dark cycle. The SCN transmits time signals to the brain and then to the whole body and by means of its time signals the SCN keeps a temporal order in diverse oscillations of the body and adjusted to the light-dark cycle. The correct temporal order enables an individual to adequate functioning in harmony with the external cycles. Biological rhythms have a hereditary character, thus its expression is genetically determined. All animals, plants, and probably all organism show some type of physiological rhythmic variation (metabolic rate, production of heat, flowering, etc.) that allow for the adaptation to a rhythmic environment. Biological rhythms enable individuals to anticipate and to be prepared to the demands of the prominent cyclic environmental changes, which are necessary for survival. Also, biological rhythms promote showing maximum levels of a physiological variable at the right moment when the environment requires a maximal response. In humans, an example of circadian rhythms is the sleep-wake cycle; simultaneously, a series of physiological changes are exhibited, also with circadian characteristics (close to 24 hours). Circadian oscillations are observed in the liberation of luteinizant hormone, in plasma cortisol, leptin, insulin, glucose and growth hormone just to mentions some examples. The SCN controls circadian rhythmicity via projections to the autonomic system and by controlling the hypothalamus-adenohipofisis-adrenal axis. In this way, the SCN transmits phase and period to the peripheral oscillators to maintain an internal synchrony. Modern life favors situations that oppose the time signals in the environment and promote conflicting signals to the SCN and its effectors. The consequence is that circadian oscillators uncouple from the master clock and from the external cycles leading to oscillations out of synchrony with the environment, which is known as internal desynchronization. The consequence is that physiological variables reach their peak expression at wrong moments according to environmental demands leading then to deficient responses and to disease in the long run. Also, levels of attention, learning and memory reach peak expression at wrong moments of the day leading individuals to exhibit a deficient performance at school or work. The disturbed sleep patterns promote fatigue and irritability, which difficult social interaction. Internal desynchronization results from transmeridional traveling for which people pass multiple hourly regions. This results in an abrupt change in the time schedule and a syndrome known as <<jet lag>>. Frequent travelers complain about difficulties to adjust their sleep-wake cycle to the new schedule, thus resulting in fatigue, increased sleepiness and reduced attention. Jet lag results from a loss of synchrony among biological rhythms and among diverse functions, which remain out of phase with the day-night cycle. This <<internal desynchrony>> is the cause of general discomfort, decrement in the physical and mental performance, as well as irritability and depression. Frequently, gastrointestinal disorders are a by-product of food consumption at an unusual schedule. The state of internal desynchrony is transitory and depends on the number of time zones that were crossed; thus, adaptation to a new external cycle can take from four to seven days. Another example of internal desynchrony is observed in individuals exposed to work shifts or to nocturnal work schedules (night work). In such conditions, circadian fluctuations in behavioral, hormonal and metabolic parameters are observed but their temporary relation with the external cycles is modified. The internal synchrony is thus affected by troubled environmental signs, out of phase with the daily activities of the individual; among them are the hours of food intake, the exposure to light during resting hours, the low temperature of the night, and the forced activity when homeostatic processes indicate a need to rest. This internal desynchrony leads to gastrointestinal disorders, disturbed metabolic fluctuations, disturbed cardiovascular functions, altered menstrual cycle, sleep disorders, sleepiness, increase of work accidents, etc. Internal desynchrony is especially due to the fact that circadian fluctuations are influenced by daily external cycles, but also by homeostatic factors, and can suffer from additional disturbance by sleep deprivation. Despite years of night work experience, incapacity to adapt to night work may persist. Only a minority of shift workers achieve spontaneous adjustment of the rhythms of core body temperature, melatonin, cortisol, thyroid stimulating hormone, or prolactin secretion to shifts by nocturnal work. Therefore shift and night workers develop a propensity to smoke, drink alcoholic beverages and use stimulant products. After five years of shift or night work, health problems appear with a higher incidence than in the general population. The growing social demand of shift work makes it necessary to decide on the characteristics and forms of shifts to carry out, and up to now organizing such working schedules remaing a serious problem. The improvement of health services has increased life expectancies and thus the general population is becoming old and people survive more years. Older people ail from health and behavioral problems including a deterioration of the biological rhythms. Main alterations consist of a loss of expression of the circadian functions or a decrease of the amplitude of the rhythms, and instability of synchronization mechanisms day by day. All in all, this implies a decreased capacity of the clock to adjust to the solar day. The decreased efficacy of the aging biological clock is evident in the fragmented sleep patterns and the disturbed sleep/wake rhythms, characterized by short sleep episodes during the day and decreased sleep during the night. Some studies suggest that the disturbed circadian rhythms may be the cause of diverse diseases associated with the elderly. In conclusion, during the last 100 years we have changed our lifestyle so radically that we lack already a physiological design to adapt so quickly to modernity. We can state that our body is designed for a world that does not exist. In this article we present a review of the main alterations of the biological rhythms generated by the transmeridional trips, shift-work and aging, their behavioral and physiological consequences that lead to disease and poor mental performance. We also discuss possible strategies that need to be explored and that may help people to improve their quality of life and to prevent internal desynchrony.<hr/>La vida se rige por una estructura temporal que gobierna nuestras horas, nuestros días y nuestros calendarios. Como parte de la adaptación a los ciclos de tiempo que impone el planeta, todo organismo presenta ritmos en su actividad y fisiología. Los ritmos biológicos son una propiedad conservada en todos los niveles de organización, desde organismos unicelulares procariontes hasta plantas superiores y mamíferos. De ellos, los más sólidos son aquellos asociados a los ciclos externos por la alternancia del día y la noche y por la alternancia de las estaciones del año. Los ritmos biológicos fisiológicos y conductuales son procesos dependientes de un reloj interno capaz de ajustar sus oscilaciones a claves de tiempo externas que lo mantienen sincronizado a estas fluctuaciones externas. El núcleo supraquiasmático del hipotálamo (NSQ) es en los mamíferos el principal reloj circadiano y se sincroniza principalmente por el ciclo luz-oscuridad. El NSQ transmite señales de tiempo al cerebro y de ahí al resto del organismo, y por medio de estas señales de tiempo mantiene un orden temporal en diversas funciones del cuerpo y las mantiene ajustadas al ciclo luz-oscuridad. El correcto orden temporal interno permite un adecuado funcionamiento del individuo en armonía con el medio externo y le permite exhibir respuestas adecuadas a un ambiente cambiante y predecible. El estilo de vida del hombre moderno propicia situaciones que llevan a alteraciones de nuestros ritmos biológicos que causan una desadaptación temporal, que a su vez redunda en daños a la salud, ya que afecta tanto la fisiología como la forma en que organizamos nuestra conducta. Un ejemplo de ello son los viajes a través de múltiples regiones horarias. Estos cambios de horario bruscos provocan un síndrome conocido como jet-lag, que consiste en un conflicto transitorio entre el tiempo <<interno>> y el tiempo <<externo>>, lo cual se denomina <<desincronización interna>>. El jet-lag se define como un conjunto de síntomas causados por una alteración del patrón de sueño, y de la expresión de ritmos biológicos fuera de fase entre sí y fuera de fase con el ciclo del día y la noche. Esta es la causa del malestar general, el deterioro del desempeño mental y físico, así como de la irritabilidad y depresión. Son frecuentes también las alteraciones gastrointestinales, resultado del consumo de alimento en un horario inusual. Otro ejemplo de alteraciones en los ritmos circadianos se observa en los trabajadores con turnos rotatorios o en turnos nocturnos. En estas condiciones se produce un conflicto entre las señales temporales asociadas al ciclo diurno y que transmite el reloj con las actividades y alimentos del trabajador en turnos. De este esquema de trabajo resulta una reducción de las horas de sueño y una alteración de los ritmos circadianos, que llevan a una desincronización interna. Ésta, al igual que en el caso del jet-lag, redunda en un deterioro de las funciones mentales y de la capacidad de atención y memorización, que se asocian a irritabilidad y problemas emocionales. Además, se observan consecuencias en la salud con incremento en la incidencia de malestares gastrointestinales, enfermedades cardiovasculares, obesidad y diabetes. La mejoría en los servicios de salud ha incrementado las expectativas de vida, lo que entonces enfrenta a la humanidad a una población que logra sobrevivir muchos años de su vejez con los cambios de conducta y salud propios de su edad, entre los que se incluye un deterioro de los ritmos biológicos. En este trabajo presentamos una revisión de las principales alteraciones de los ritmos biológicos generadas por los viajes transmeridionales, la vejez y el trabajo en turnos. También discutimos la relevancia de una buena adaptación de los ritmos biológicos y las consecuencias conductuales y fisiológicas que por su alteración llevan a la enfermedad y a un desempeño mental deficiente. También sugerimos estrategias que necesitan ser exploradas y que podrían ayudar prevenir la desincronización interna para mejorar la calidad de vida. <![CDATA[<b>Autoevaluación</b>]]> http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0185-33252009000100012&lng=pt&nrm=iso&tlng=pt Life on our planet is ruled by a temporary structure that governs our activities, our days and our calendars. In order to cope with a daily changing environment, organisms have developed adaptive strategies by exhibiting daily behavioral and physiological changes. Biological rhythms are properties conserved in all the levels of organization, from unicellular to prokaryotes to upper plants and mammals. A biological rhythm is defined as the recurrence of a biological phenomenon in regular intervals of time. Biological rhythms in behaviour and physiology are controled by an internal clock which synchronizes its oscillations to external time cues that have the capacity to adjust the clock's mechanism and keep it coupled to external fluctuations. The suprachiasmatic nucleus (SCN) of the hypothalamus in mammals is the master circadian clock which is mainly entrained by the light-dark cycle. The SCN transmits time signals to the brain and then to the whole body and by means of its time signals the SCN keeps a temporal order in diverse oscillations of the body and adjusted to the light-dark cycle. The correct temporal order enables an individual to adequate functioning in harmony with the external cycles. Biological rhythms have a hereditary character, thus its expression is genetically determined. All animals, plants, and probably all organism show some type of physiological rhythmic variation (metabolic rate, production of heat, flowering, etc.) that allow for the adaptation to a rhythmic environment. Biological rhythms enable individuals to anticipate and to be prepared to the demands of the prominent cyclic environmental changes, which are necessary for survival. Also, biological rhythms promote showing maximum levels of a physiological variable at the right moment when the environment requires a maximal response. In humans, an example of circadian rhythms is the sleep-wake cycle; simultaneously, a series of physiological changes are exhibited, also with circadian characteristics (close to 24 hours). Circadian oscillations are observed in the liberation of luteinizant hormone, in plasma cortisol, leptin, insulin, glucose and growth hormone just to mentions some examples. The SCN controls circadian rhythmicity via projections to the autonomic system and by controlling the hypothalamus-adenohipofisis-adrenal axis. In this way, the SCN transmits phase and period to the peripheral oscillators to maintain an internal synchrony. Modern life favors situations that oppose the time signals in the environment and promote conflicting signals to the SCN and its effectors. The consequence is that circadian oscillators uncouple from the master clock and from the external cycles leading to oscillations out of synchrony with the environment, which is known as internal desynchronization. The consequence is that physiological variables reach their peak expression at wrong moments according to environmental demands leading then to deficient responses and to disease in the long run. Also, levels of attention, learning and memory reach peak expression at wrong moments of the day leading individuals to exhibit a deficient performance at school or work. The disturbed sleep patterns promote fatigue and irritability, which difficult social interaction. Internal desynchronization results from transmeridional traveling for which people pass multiple hourly regions. This results in an abrupt change in the time schedule and a syndrome known as <<jet lag>>. Frequent travelers complain about difficulties to adjust their sleep-wake cycle to the new schedule, thus resulting in fatigue, increased sleepiness and reduced attention. Jet lag results from a loss of synchrony among biological rhythms and among diverse functions, which remain out of phase with the day-night cycle. This <<internal desynchrony>> is the cause of general discomfort, decrement in the physical and mental performance, as well as irritability and depression. Frequently, gastrointestinal disorders are a by-product of food consumption at an unusual schedule. The state of internal desynchrony is transitory and depends on the number of time zones that were crossed; thus, adaptation to a new external cycle can take from four to seven days. Another example of internal desynchrony is observed in individuals exposed to work shifts or to nocturnal work schedules (night work). In such conditions, circadian fluctuations in behavioral, hormonal and metabolic parameters are observed but their temporary relation with the external cycles is modified. The internal synchrony is thus affected by troubled environmental signs, out of phase with the daily activities of the individual; among them are the hours of food intake, the exposure to light during resting hours, the low temperature of the night, and the forced activity when homeostatic processes indicate a need to rest. This internal desynchrony leads to gastrointestinal disorders, disturbed metabolic fluctuations, disturbed cardiovascular functions, altered menstrual cycle, sleep disorders, sleepiness, increase of work accidents, etc. Internal desynchrony is especially due to the fact that circadian fluctuations are influenced by daily external cycles, but also by homeostatic factors, and can suffer from additional disturbance by sleep deprivation. Despite years of night work experience, incapacity to adapt to night work may persist. Only a minority of shift workers achieve spontaneous adjustment of the rhythms of core body temperature, melatonin, cortisol, thyroid stimulating hormone, or prolactin secretion to shifts by nocturnal work. Therefore shift and night workers develop a propensity to smoke, drink alcoholic beverages and use stimulant products. After five years of shift or night work, health problems appear with a higher incidence than in the general population. The growing social demand of shift work makes it necessary to decide on the characteristics and forms of shifts to carry out, and up to now organizing such working schedules remaing a serious problem. The improvement of health services has increased life expectancies and thus the general population is becoming old and people survive more years. Older people ail from health and behavioral problems including a deterioration of the biological rhythms. Main alterations consist of a loss of expression of the circadian functions or a decrease of the amplitude of the rhythms, and instability of synchronization mechanisms day by day. All in all, this implies a decreased capacity of the clock to adjust to the solar day. The decreased efficacy of the aging biological clock is evident in the fragmented sleep patterns and the disturbed sleep/wake rhythms, characterized by short sleep episodes during the day and decreased sleep during the night. Some studies suggest that the disturbed circadian rhythms may be the cause of diverse diseases associated with the elderly. In conclusion, during the last 100 years we have changed our lifestyle so radically that we lack already a physiological design to adapt so quickly to modernity. We can state that our body is designed for a world that does not exist. In this article we present a review of the main alterations of the biological rhythms generated by the transmeridional trips, shift-work and aging, their behavioral and physiological consequences that lead to disease and poor mental performance. We also discuss possible strategies that need to be explored and that may help people to improve their quality of life and to prevent internal desynchrony.<hr/>La vida se rige por una estructura temporal que gobierna nuestras horas, nuestros días y nuestros calendarios. Como parte de la adaptación a los ciclos de tiempo que impone el planeta, todo organismo presenta ritmos en su actividad y fisiología. Los ritmos biológicos son una propiedad conservada en todos los niveles de organización, desde organismos unicelulares procariontes hasta plantas superiores y mamíferos. De ellos, los más sólidos son aquellos asociados a los ciclos externos por la alternancia del día y la noche y por la alternancia de las estaciones del año. Los ritmos biológicos fisiológicos y conductuales son procesos dependientes de un reloj interno capaz de ajustar sus oscilaciones a claves de tiempo externas que lo mantienen sincronizado a estas fluctuaciones externas. El núcleo supraquiasmático del hipotálamo (NSQ) es en los mamíferos el principal reloj circadiano y se sincroniza principalmente por el ciclo luz-oscuridad. El NSQ transmite señales de tiempo al cerebro y de ahí al resto del organismo, y por medio de estas señales de tiempo mantiene un orden temporal en diversas funciones del cuerpo y las mantiene ajustadas al ciclo luz-oscuridad. El correcto orden temporal interno permite un adecuado funcionamiento del individuo en armonía con el medio externo y le permite exhibir respuestas adecuadas a un ambiente cambiante y predecible. El estilo de vida del hombre moderno propicia situaciones que llevan a alteraciones de nuestros ritmos biológicos que causan una desadaptación temporal, que a su vez redunda en daños a la salud, ya que afecta tanto la fisiología como la forma en que organizamos nuestra conducta. Un ejemplo de ello son los viajes a través de múltiples regiones horarias. Estos cambios de horario bruscos provocan un síndrome conocido como jet-lag, que consiste en un conflicto transitorio entre el tiempo <<interno>> y el tiempo <<externo>>, lo cual se denomina <<desincronización interna>>. El jet-lag se define como un conjunto de síntomas causados por una alteración del patrón de sueño, y de la expresión de ritmos biológicos fuera de fase entre sí y fuera de fase con el ciclo del día y la noche. Esta es la causa del malestar general, el deterioro del desempeño mental y físico, así como de la irritabilidad y depresión. Son frecuentes también las alteraciones gastrointestinales, resultado del consumo de alimento en un horario inusual. Otro ejemplo de alteraciones en los ritmos circadianos se observa en los trabajadores con turnos rotatorios o en turnos nocturnos. En estas condiciones se produce un conflicto entre las señales temporales asociadas al ciclo diurno y que transmite el reloj con las actividades y alimentos del trabajador en turnos. De este esquema de trabajo resulta una reducción de las horas de sueño y una alteración de los ritmos circadianos, que llevan a una desincronización interna. Ésta, al igual que en el caso del jet-lag, redunda en un deterioro de las funciones mentales y de la capacidad de atención y memorización, que se asocian a irritabilidad y problemas emocionales. Además, se observan consecuencias en la salud con incremento en la incidencia de malestares gastrointestinales, enfermedades cardiovasculares, obesidad y diabetes. La mejoría en los servicios de salud ha incrementado las expectativas de vida, lo que entonces enfrenta a la humanidad a una población que logra sobrevivir muchos años de su vejez con los cambios de conducta y salud propios de su edad, entre los que se incluye un deterioro de los ritmos biológicos. En este trabajo presentamos una revisión de las principales alteraciones de los ritmos biológicos generadas por los viajes transmeridionales, la vejez y el trabajo en turnos. También discutimos la relevancia de una buena adaptación de los ritmos biológicos y las consecuencias conductuales y fisiológicas que por su alteración llevan a la enfermedad y a un desempeño mental deficiente. También sugerimos estrategias que necesitan ser exploradas y que podrían ayudar prevenir la desincronización interna para mejorar la calidad de vida.