Externalizing disorders in consecutively referred children and adolescents with bipolar disorder

We describe a consecutive clinical sample of children and adolescents with bipolar disorder (BD), in order to define the pattern of comorbid externalizing disorders and to explore the possible influence of such a comorbidity on their cross-sectional and longitudinal clinical characteristics. The sample consisted of 59 bipolar patients: 35 males and 24 females, with a mean age 14.6 +/- 3 years (range, 7 to 18 years), diagnosed as either type I or II according to DSM-IV. All patients were screened for psychiatric disorders using historical information and a clinical interview, the Diagnostic Interview for Children and Adolescents-Revised (DICA-R). Severity and subsequent outcome of the symptomatology were recorded with the Clinical Global Impression (CGI), Severity and Improvement Scales, at the baseline and thereafter monthly for a period up to 48 months. BD disorder type I was present in 37 (62.7%) of the patients; 14 (23.7%) were affected by attention deficit-hyperactivity disorder (ADHD) and 10 (16.9%) by conduct disorder (CD). Comorbid ADHD was associated with an earlier onset of BD, while CD was highly associated with BD type I. Anxiety disorders appeared more represented in patients without CD. At the end of the observation, a lower clinical improvement was recorded in patients with CD. In our children and adolescents with BD, comorbidity with externalizing disorders such as ADHD and CD is common. The clinical implications of comorbid ADHD and CD are rather different. ADHD can be viewed as a precursor of a child-onset subtype of BD, while CD might represent a prodromal or a concomitant behavioral complication that identifies a more malignant and refractory form of BD.