Resumen

PALACIOS CRUZ, Lino et al. Attention Deficit Hyperactivity Disorder and Pediatric Bipolar Disorder, comorbidity or overlap?: A Review. Part One. Salud Ment [online]. 2008, vol.31, n.1, pp.19-22. ISSN 0185-3325.

Attention deficit/hyperactivity disorder (ADHD) can present itself with a wide variety of comorbid psychiatric entities and can easily be misdiagnosed with disorders such as the pediatric bipolar disorder (PedBP), making early detection and treatment difficult. The main objective of this review is to evaluate the relationship between PedBP and ADHD. Several studies have addressed this association, establishing a high rate of comorbidity, from 57% to 93%. The risk of developing PedBP in ADHD population has also been studied, documenting a ten-fold increase risk in both genders compared with age-matched healthy controls. Pediatric bipolar disorder is still a diagnostic entity which is hard to recognize and differentiate from other disorders, even with the current international diagnostic criteria. Individuals with ADHD with a current depressive episode, suicide attempts and/or substance abuse and that carry a family load (mainly parents) for bipolar disorder are at increased risk of actually having this disorder. Several researchers have compared clinical symptoms expressed in children with ADHD and PedBP. They have found that children with PedBP exhibit higher frequency of elated mood, increased energy, thought disorder, flight of ideas, increased speed in speech and irritability than those with ADHD. Other authors report higher rates of thought disorders, anxiety, depression, aggression and delinquent behavior amongst children with PedBP than those with ADHD. It has also been reported that children with PedBP compared to those with ADHD present higher rates of euphoria, grandiosity, racing thoughts and decreased need for sleep. Yet another study found that euphoria and increased energy distinguished youths with PedBP from those with other psychiatric disorders, and found that with the group of depressed patients exhibit higher rates of suicidal thoughts and behavior than other diagnostic groups. Some cues to diagnose and differentiate PedBP and ADHD have been proposed: ADHD symptoms appearing suddenly or later in life, loss of therapeutic response to stimulants in a previous responder, intermittent symptoms, emergence of elated mood and decreased need for sleep, severe mood shifting, hallucinations or thought disorders, family history of bipolar disorder and lack of response to adequate treatment. Three of the seven criteria for bipolar disorder are shared with ADHD (distractibility, increased goal directed activity and talkativeness), making the clinical distinction between ADHD and early onset PedBP a difficult task. In fact, most children diagnosed with PedBP present symptoms and behavior compatible with a simultaneous ADHD. The role of ADHD as a prodromic, phenocopy, comorbid condition and/or as a misdiagnosis for PedBP can be further clarified by: 1. case follow-up to determine if comorbid diagnosis can predict the course or determine a prognosis factor; and 2. family genetic studies which are convenient for the evaluation of complex comorbid conditions. Some studies have suggested that this comorbid syndrome may possess a specific genotype, as well a particular course, a pattern of treatment response and may represent a distinctive clinical condition. High comorbidity BPD, both in adult and child and adolescent populations, runs a similar pattern to that of other important diagnostic categories in child and adolescent psychiatry. From a clinical perspective, these findings support the notion of avoiding hierarchical diagnoses. Furthermore, it questions the vision of categorical entities as it is proposed in the current diagnostic classification (ICD and DSM). Currently, when we talk about ADHD, we cannot separate it from other disruptive behavior disorders, such as conduct disorder (CD) and oppositional-defiant disorder (ODD). Epidemiological studies show that 40% to 70% of children with ADHD have CD or ODD, and some of them also present comorbid internalizing disorders. There is a clear possibility of a diagnostic confussion between PedBP and disruptive behavior disorders. Certain behavioral signals can indicate whether a child has a PedBP and/or a ODD or CD. The role sequential or concurrent comorbidity plays on neuropsychological profiles or neuroanatomy of bipolar disorder and ADHD remains unclear. Independent reports indicate an overlap of the neural circuits implicated on both disorders. Apparently, there is an overlap of impairments in ADHD children with and without PedBP involving motor inhibitory control, sustained attention, verbal learning, working memory, planning, and visual and motor skills. In addittion, to making both the early detection and diagnosis more difficult, comorbidity between ADHD and PedBP in the clinical setting complicates pharmacological and psychotherapeutic treatment. Pharmacologically, some studies have suggested that stimulant use may be safe and effective in children with manic symptoms and ADHD. Other reports argue against their use, hence these findings are not conclusive. An alternative for the pharmacological management of the ADHD/PedBP comorbidity is the use of atomoxetine, although there are no randomized, double blind or clinical controlled trials to support its use. It has been reported that BP and ADHD comorbidity may predict a lack of response to lithium pharmacotherapy in adolescents. Few studies have the addressed response to divalproex with this comorbidity. Data also suggest a lack of response in manic phases to usual pharmacotherapy in bipolar patients with a history of ADHD. These data stress the importance of the detection of comorbid ADHD (active or in remission) for prognostic and therapeutic planning. Furthermore, it is necessary to research on novel treatment modalities to specifically address the comorbid condition. In our country, efforts have been made to address the ADHD-PedBP comorbidity. One example is the treatment algorithm for ADHD and PedBP proposed by the Second Expert Consensus on the management of Attention Deficit/Hyperactivity disorder, an effort made towards adapting the available evidence and treatment options for our population. The algorithm establishes that at STAGE 0 the crucial aspect is early detection. Bipolar disorder should be addressed first and it ought to be done by a specialist. Some important points in STAGE 1 are: 1. first treatment option should be a stimulant (in Mexico, immediate and controlled release methylphenidate ) plus a mood stabilizer; 2. in the case of a lack of response to two different stimulants, atomoxetine or bupropion should be considered; 3. as a last option, atypical antipsychotics like risperidone, olanzapine, quetiapine and aripiprazole are proposed. It also mentions the ever frequent need for combined therapy and dynamic modifications in treatment sequences. Conclusions ADHD and PedBP disorder are highly comorbid. The similarities between the clinical features of these entities often make diagnosis a challenge for clinicians and carries several treatment considerations. In accordance to international research and national efforts to establish treatment options, stimulants may be considered a first line option for ADHD/BP comorbidity with the addition of a mood stabilizer. Although in general stimulants may be benefitial to many patients with both ADHD and B P, a group of patients may not tolerate their use, mainly due to side effects or mood destabilization. To offer a better treatment option for these patients it is crucial to continue in the search for other therapeutic modalities in order to improve residual symptoms in attention and cognition, even when the affective symptoms have resided.

Palabras llave : Attention and hyperactivity disorder; pediatric bipolar disorder; comorbidity.

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