Meta-analysis of personal and familial co-occurrence of Attention Deficit/Hyperactivity Disorder and Bipolar Disorder.

BACKGROUND:Attention Deficit Disorder / Hyperactivity (ADHD) and Bipolar Disorder (BD) are highly comorbid disorders. Studies have raised the hypothesis of shared genetic, neurobiological, and clinical factors. This would entail an excess risk of co-occurrence of both disorders. OBJECTIVE:We present the first meta-analysis of individual and familial associations between ADHD and BD. METHODS:From 2688 references, 59 were included, with a total of 550,379 ADHD patients, 57,799 BD patients and 12,608,137 controls. RESULTS:Personal history of ADHD increased the risk of BD (OR = 6.06), and conversely individuals with BD had an increased risk of ADHD (OR = 8.94). First-degree relatives of ADHD patients had an increased risk of BD (OR = 1.94). Offspring of individuals with BD had a higher risk for ADHD (OR = 2.33). Finally, first-degree relatives of BD patients had an increased risk of ADHD (OR = 2.71). CONCLUSION:We show a clear epidemiological overlap between ADHD and BD, as well as a strong familial association which advocates in favor of a more systematic screening.