Attention deficit-hyperactivity disorder and early-onset bipolar disorder: two facets of one entity?

Abstract

Early-onset bipolar disorder (BD) and attention-deficit-hyperactivity disorder (ADHD) have recently been the subject of highly controversial debate, due to theories regarding underlying pathophysiological processes and a clinical overlap of symptoms. Epidemiological data, clinical aspects neuroimaging, neurochemical, and genetic studies suggest that there may be a possible relationship between biological factors and clinical characteristics in the development of symptoms. However, longitudinal data supporting the hypothesis of a diagnostic shift from BD to ADHD symptoms and vice versa are currently not available. These would be essential to enable further investigations into whether these two disorders possibly represent two different aspects of an underlying common psychopathophysiological entity.