Is comorbidity with ADHD a marker for juvenile-onset mania?

OBJECTIVE: To compare the characteristics and correlates of mania in referred adolescents and to determine whether attention-deficit hyperactivity disorder (ADHD) is a marker of very early onset mania. METHOD: From 637 consecutive admissions, 68 children (< or = 12 years) and 42 adolescents (> 13 years) who satisfied criteria for mania were recruited. These were compared with the 527 nonmanic referrals and 100 normal controls. RESULTS: With the exception of comorbidity with ADHD, there were more similarities than differences between the children and adolescents with mania in course and correlates. There was an inverse relationship between the rates of comorbid ADHD and age of onset of mania: higher in manic children intermediate in adolescents with childhood-onset mania, and lower in adolescents with adolescent-onset mania. CONCLUSIONS: ADHD is more common in childhood-onset compared with adolescent-onset cases of bipolar disorder, suggesting that in some cases, ADHD may signal a very early onset of bipolar disorder. Clinical similarities between the child- and adolescent-onset cases provide evidence for the clinical validity of childhood-onset mania.