Study Examines Comorbidity of ADHD and Bipolar Disorder
In a 2021 review and meta-analysis in the journal Neuroscience and Biobehavioral Reviews, researcher Carmen Schiweck and colleagues described the comorbidity of attention-deficit hyperactivity disorder (ADHD) and bipolar disorder in adults. This was the first review and meta-analysis to quantify the comorbidity of the two fairly prevalent disorders. The meta-analysis included 71 studies with a combined total of 646,766 participants from 18 countries.
The review found that among people with ADHD, about 1 in 13 also have bipolar disorder, while among people with bipolar disorder, 1 in 6 have comorbid ADHD. The prevalence differed depending on the continent where patients lived and the diagnostic systems used there, with greater prevalence of both disorders in the US, where the Diagnostic and Statistical Manual of Mental Disorders is used, than in Europe, where the International Classification of Diseases is typically used. (Other parts of the world were less represented in the meta-analysis.) Schiweck and colleagues found that bipolar disorder had an onset about 4 years earlier in patients who had comorbid ADHD.
