Resumo

BOJORQUEZ CHAPELA, Ietza  e  SALGADO DE SNYDER, Nelly. Psychometric characteristics of the Center for Epidemiological Studies-depression Scale (CES-D), 20-and 10-item versions, in women from a Mexican rural area. Salud Ment [online]. 2009, vol.32, n.4, pp.299-307. ISSN 0185-3325.

Depressive symptoms constitute a common mental health problem, with a relevant social and personal impact. These symptoms are present not only among the urban population in more economically developed countries, but also in rural areas in poor and middle development countries. In order to obtain reliable information on the frequency of depressive symptoms, their risk factors or the impact of preventive and clinical measures, valid measurement instruments are needed. Radloff's Center for Epidemiological Studies - Depression scale (CES-D) was originally developed for the study of depressive symptoms in an open population. While the CES-D is not useful for the evaluation of depressive disorders according to psychiatric criteria, it can still yield useful information about the presence of depressed mood, feelings of guilt and worthlessness, feelings of helplessness and hopelessness, psychomotor retardation, and somatic complaints, which constitute dimensions of depression. The instrument has been shown to be valid in culturally diverse groups. It has also been shown to correlate with the clinical diagnosis of depression, with sensibility as high as 100%, while its specificity has been reported as 57-88%. Shorter versions of the CES-D have been developed. Their advantages include a more easy inclusion in ample questionnaires, and their being less tiresome for respondents. The main objective of this study was to evaluate the psychometric properties of CES-D, both the original, 20- item version, and the 10-item version by Andresen et al., in women living in the Mixteca, a poor rural area which includes part of the states of Guerrero, Oaxaca and Puebla, in southern Mexico. The instrument was applied as part of a comprehensive survey on health and migration in three rural municipalities in the Mixteca. The sampling design included cluster, proportional to size sampling of localities, and systematic selection of households. At each household, one woman of between 15 and 49 years of age responded a questionnaire which included the CES-D. A total of 468 women were included in the sample (median 35 years, interquartile range 28, 42). Of these, 89% were married or had a stable partner, 5% were single, 13% separated, and 12% widowed. The majority (65%) had only six years of schooling, while 1 6% had no formal education. The statistical analysis was conducted on the 343 questionnaires with complete answers to the CES-D (73% of the sample). The mean score in CES-D-20 was 11.3 (standard deviation 8.8). The mean score in CES-D-10 was 6.3 (standard deviation 5.0). According to the respective cut-off points, prevalence of depressive symptoms was 24.5% for the CES-D-20 and 22.3% for CES-D-1 0. A descriptive statistical analysis of the scores in each item and in the complete scales was conducted. In order to evaluate the internal consistency of CES-D, both 1 0- and 20- item versions, inter-item and item-total correlations were calculated. Cronbach's alpha coefficient was also obtained. Factor analysis was employed to determine if the actual aggregation of the items was coherent with the theoretical dimensions they were intended to measure. Another way to prove validity was through the analysis of the association between the score in the CES-D and the answers to questions about <<nervios>>, an ethnical syndrome well recognized in the region and sharing characteristics with depression. Also, the association of scores with other variables known to be related to depressive symptoms, such as being chronically ill or the educational level, was investigated. In order to evaluate CES-D-10 capacity to identify depressive symptoms, taking the CES-D-20 as reference, Spearman's correlation coefficient between the scores in both scales was calculated. The kappa statistic was employed to evaluate the concordance between scales in the classification of individuals according to their respective cut-off points. For CES-D-20, Cronbach's alpha value was 0.84 and for CES-D-10 it was 0.74. For CES-D-20, four factors with eigen values over 1 were extracted, accounting for 50.6% of variance. The first one included items which, according to Radloff's original solution, are part of the dimensions depressed affect, retarded activity, and positive affect. The second one included items from the depressed affect, retarded activity, and interpersonal dimensions. The fourth factor included only two items, both from the positive affect dimension. A scree plot showed that a two factor solution could also be adequate. For CES-D-10, two factors were extracted, accounting for 46.5% of variance. As for convergent validity, women who reported having <<nervios>> had a median CES-D-20 score of 13.5 (IQR 8.8, 22), while those who did not report the illness had a median score of 9 (IQR 4, 14). Women without a formal education had a median CES-D-20 score of 1 2 (IQR 8, 20), those who had completed elementary school had a median score of 10 (IQR 5, 15), and those with junior high or over had a median of 8 (IQR 3, 15). Those who reported having a chronic illness had a median score of 12 (IQR 8, 18), while those without a chronic illness had a median of 8 (IQR 4, 13). Similar results were observed for the CES-D-10. Spearman's correlation coefficient between CES-D-20 and CES-D-10 was 0.94 (p<.0001). Kappa value for concordance between both versions of the scale was of 0.80. In comparison to the longer version, CES-D-10 had a sensibility of 79.8% and a specificity of 97.3% for the detection of those over cut-off point. The results show that both scales had good reliability and validity in relation to measures of other variables related to depressive symptoms. The factorial grouping of the items was different from the original, as has been observed by other authors. A similar, unimodal distribution centered in 0 and with a positive skew was observed for the answers to all items, except for two items with a bimodal distribution. Those two items were also different to the rest in their presence (having the symptom at least on day during the past week) and persistence (having the symptom everyday during the past week). These differences suggest that items 4 and 8 of the CES-D could have validity problems in this population. In conclusion, both versions of the CES-D were found to have good psychometric properties in this sample, with the shorter one having the advantage of being easier to include in questionnaires for more comprehensive studies. However, further studies with the use of qualitative methods should clarify the true cross-cultural validity of the CES-D in rural areas in Mexico.

Palavras-chave : Depressive symptoms; scales; validation studies; rural area; mental health.

        · resumo em Espanhol     · texto em Espanhol     · Espanhol ( pdf )