Understanding Early Age of Onset: a Review of the Last 5 Years.

The age at onset of bipolar disorder ranging from childhood to adolescent to adult has significant implications for frequency, severity and duration of mood episodes, comorbid psychopathology, heritability, response to treatment, and opportunity for early intervention. There is increasing evidence that recognition of prodromal symptoms in at-risk populations and mood type at onset are important variables in understanding the course of this illness in youth. Very early childhood onset of symptoms including anxiety/depression, mood lability, and subthreshold manic symptoms, along with family history of a parent with early onset bipolar disorder, appears to predict the highest risk of early onset disorder with the most severe course.