A systematic review of the frequency and severity of manic symptoms reported in studies that compare phenomenology across children, adolescents and adults with bipolar disorders.

In the last two decades, there has been a significant increase in the diagnosis of Bipolar Disorder (BD) in children. The notion of prepubertal onsets of BD is not without controversy, with researchers debating whether paediatric cases have a distinct symptom profile or follow a different illness trajectory from other forms of BD. The latter issue is difficult to address without long-term prospective follow-up studies. However, in the interim, it is useful to consider the phenomenology observed in groups of cases with different ages of onset and particularly to compare manic symptoms in children diagnosed with BD compared to cases presenting with BD in adolescence and adulthood. This review systematically explores the phenomenology of manic or hypomanic episodes in groups defined by age at onset of BD (children, adolescents and adults; or combined age groups e.g. children and adolescents versus adults).