Attention deficit hyperactivity disorder or juvenile bipolar affective disorder

This article reviews research on juvenile bipolar disorder and attention deficit hyperactivity disorder (ADHD) with particular reference to differential diagnosis and treatment. Systematic research strongly suggests an atypical course of very early onset bipolar disorder. Atypicality of such phenotype may not be rare, but is difficult to diagnose. A main cause of diagnostic confusion is symptomatic overlap between juvenile bipolar disorder phenotype and attention deficit hyperactivity disorder. A very important question is whether child, adolescent and adult onset bipolar disorder could be an unrelated disorder, or a different developmental expression of the same disorder. The role of neuropsychological and neuroimaging studies in differential diagnosis of very early onset bipolar disorder and ADHD is discussed.