Anxiety disorders in children and adolescents with bipolar disorder: a neglected comorbidity.

Objective: We describe a consecutive clinical sample of children and adolescents with bipolar disorder to define the pattern of comorbid anxiety and externalizing disorders (attention-deficit hyperactivity disorder [ADHD] and conduct disorder [CD]) and to explore the possible influence of such a comorbidity on their cross-sectional and longitudinal clinical characteristics.

Methods: The sample comprised 43 outpatients, 26 boys and 17 girls, (mean age 14.9 years, SD 3.1; range 7 to 18), with bipolar disorder type I or II, according to DSM-IV diagnostic criteria. All patients were screened for psychiatric disorders using historical information and a clinical interview, the Diagnostic Interview for Children and Adolescents-Revised (DICA-R). To shed light on the possible influence of age at onset, we compared clinical features of subjects whose bipolar onset was prepubertal or in childhood (< 12 years) with those having adolescent onset. We also compared different subgroups with and without comorbid externalizing and anxiety disorders.

Results: Bipolar disorder type I was slightly more represented than type II (55.8% vs 44.2%). Only 11.6% of patients did not have any other psychiatric disorder; importantly, 10 subjects (23.5%) did not show any comorbid anxiety disorder. Comorbid externalizing disorders were present in 12 (27.9%) patients; such comorbidity was related to the childhood onset of bipolar disorder type II. Compared with other subjects, patients with comorbid anxiety disorders more often reported pharmacologic (hypo)mania.