Diagnostic profiles and clinical characteristics of youth referred to a pediatric mood disorders clinic.

Approximately 28% of adults with bipolar disorder (BD) report symptom onset before 13 years of age, and about 66% before 18 years (1). Early onset is often associated with a treatment-resistant course of BD in adulthood, with a high prevalence of rapid cycling, mixed symptoms, comorbid disorders, suicidal behavior and functional impairment (2, 3). Misdiagnosing BD in children can have significant adverse consequences for the long-term management of the disorder (4). The prevalence of clinical diagnoses of pediatric BD increased 40-fold between 1993 and 2003 (5), although it is not clear whether this increase reflects true over-diagnosis or the lack of recognition of early-onset BD prior to 1990. It is estimated that approximately 95,000 children and adolescents were receiving medications for bipolar disorder in the United States as of 2001 (6). In contrast, a meta-analysis of 12 clinical studies of pediatric bipolar disorder (including BD I, II, and NOS) found a 2% prevalence rate in the United States as well as in other countries (including Mexico, the Netherlands, Ireland, the United Kingdom, and Spain; 7). Furthermore, there was no evidence of a temporal increase in the community prevalence of BD during the two decades spanned by these studies. The National Comorbidity Survey-Revised reported a 2%–4% prevalence rate of bipolar spectrum disorders (BSDs) among adolescents, defined as bipolar I, II, not otherwise specified, or cyclothymic disorder (8); and a 2.5% lifetime rate of manic episodes among adolescents (9). Early detection and subsequent treatment of BSDs may reduce the severity, chronicity, and treatment resistance characteristic of the disorder in adulthood (10). Differential diagnosis of BSDs in children and adolescents, however, is especially challenging. First, there is a significant overlap in the symptoms of BSDs and other psychiatric disorders, notably attention deficit hyperactivity disorder (ADHD), conduct disorder, and oppositional defiant disorder (10). Second, symptoms of mania or hypomania in a depressed child or adolescent are often overlooked unless they cause clear functional impairment (11). Third, parents tend to be more reliable reporters of manic symptoms than are children, yet some clinicians rely exclusively on child report (12). Finally, a “backlash” against the possible over-diagnosis of BSDs may have caused some community clinicians to err on the side of using diagnoses such as “mood disorder not otherwise specified” or “intermittent explosive disorder” when there are doubts about the significance of (hypo)manic symptoms (13). These issues may adversely affect the reliability of community diagnoses of BSD. The primary objective of this study was to examine the diagnostic profiles of youth who were referred to a university-based child and adolescent mood disorders clinic specializing in bipolar disorder. All youth referred to the clinic had been described as having significant mood dysregulation. All had either (a) received a previous mental health evaluation resulting in a bipolar spectrum diagnosis and were seeking a second opinion, or (b) parents who recognized one or more manic symptoms in their child and were interested in diagnostic clarification and treatment recommendations. Because of the relatively low threshold for naming bipolar disorder as the primary diagnosis in community settings, we hypothesized that rates of BSDs would be much lower when diagnoses were based on structured interviews with children and one or both parents, independent psychiatrist interviews, and consensus diagnostic conferences. Secondarily, because the average age at onset of BD I and Major Depressive Disorder (MDD) is during late adolescence, we hypothesized that these diagnoses would be more likely among older adolescents than among children or preadolescents.