BACKGROUND: This study had two objectives: (1) examine characteristics of aggression in children and adolescents diagnosed with bipolar disorder and (2) determine whether the CBCL pediatric bipolar disorder profile differentiated youngsters with bipolar disorder from youngsters with ADHD.

METHOD: Children and adolescents referred to a pediatric psychopharmacology clinic were systematically evaluated for psychopathology using a psychiatrist-administered diagnostic interview, parent- and teacher-report rating scales assessing the child's behavior, and child-completed self-report scales. In this sample, 27 children and adolescents were diagnosed with bipolar disorder and 249 youngsters were diagnosed with ADHD without co-occurring bipolar disorder. These two groups were compared to determine whether there were significant differences on various measures of psychopathology.

RESULTS: Youngsters diagnosed with bipolar disorder were more verbally aggressive and exhibited higher levels of reactive aggression than youngsters with ADHD without co-occurring bipolar disorder. Youngsters with bipolar disorder also reported higher levels of depressive symptoms than youngsters with ADHD without bipolar disorder. The CBCL pediatric bipolar disorder profile did not accurately identify youngsters diagnosed with bipolar disorder.

CONCLUSIONS: The present findings present a picture of manic youngsters as verbally aggressive and argumentative, who respond with anger when frustrated. Youngsters diagnosed with bipolar disorder and ADHD exhibited significant levels of impulsive behavior and attention problems, but youngsters with bipolar disorder also exhibited significant levels of aggressive behavior and dysphoric mood. Finally, the CBCL pediatric bipolar disorder profile did not accurately identify youngsters who were diagnosed with bipolar disorder.