Prediction of transition from common adolescent bipolar experiences to bipolar disorder: 10-year study.

Background: Although (hypo)manic symptoms are common in adolescence, transition to adult bipolar disorder is infrequent.

Aims: To examine whether the risk of transition to bipolar disorder is conditional on the extent of persistence of subthreshold affective phenotypes.

Method: In a 10-year prospective community cohort study of 3021 adolescents and young adults, the association between persistence of affective symptoms over 3 years and the 10-year clinical outcomes of incident DSM-IV (hypo)manic episodes and incident use of mental healthcare was assessed.