Attention-deficit hyperactivity disorder with bipolar disorder: A familial subtype?

Objective: To clarify the nosological status of children with attention- deficit hyperactivity disorder (ADHD) who also satisfy diagnostic criteria for bipolar disorder (BPD). Method: Blind raters and structured psychiatric interviews were used to examine 140 children with ADHD, a sample of 120 non- ADHD comparisons, and their 822 first-degree relatives. Data analyses tested specific hypotheses about the familial relationship between ADHD and BPD. Results: After stratifying the ADHD sample into those with and without BPD, the authors found that (1) relatives of both ADHD sub-groups were at significantly greater risk for ADHD than relatives of non-ADHD controls; (2) the two subgroups did not differ significantly from one another in their relatives risk for ADHD; (3) a fivefold elevated risk for BPD was observed among relatives when the proband child had BPD but not when the proband had ADHD alone; (4) an elevated risk for major depression with severe impairment was found for relatives of ADHD+BPD probands; (5) both ADHD and BPD occurred in the same relatives more often than expected by chance alone; and (6) there was a trend for random mating between ADHD parents and those with mania. Conclusions: The data suggest that comorbid ADHD with BPD is familially distinct from other forms of ADHD and may be related to what others have termed childhood-onset BPD.