Objective: To investigate the rate and predictors of onset of DSM-III bipolar I and bipolar II disorders among 6- to 12-year-old prepubertal subjects with DSM-III major depressive disorder (MDD) who were followed for a 2- to 5-year period.
Methods: This was a prospective, blindly rated study of 79 children with MDD and 31 normal control children matched for age, gender, and socioeconomic status. Subjects and a second informant were assessed at 4-month intervals using the Kiddie Schedule for Affective Disorders and Schizophrenia-Present Episode Version-1986 modified to include 4-month interval ratings and to include DSM-III diagnoses. Family history (FH) was assessed using the FH-Research Diagnostic Criteria obtained from the mother about the subject's first- and second-degree relatives.
Results: Bipolarity developed in 31.7% (N = 25) of the children with MDD at a mean age of 11.2 +/- 2.0 years and 80% were prepubertal. Loaded FH and multigenerational FH were significantly associated with bipolar I. Neither prior nor current use of tricyclic antidepressants nor atypical depressive features were predictive.
Conclusions: These findings strongly support the need to educate families of children with prepubertal-onset MDD about the possibility of the emergence of manic and hypomanic symptoms to encourage early recognition and appropriate treatment.