Prevalence and symptoms at onset of bipolar illness among adolescent inpatients.

The records of 236 adolescents (116 males and 120 females) admitted to an inpatient psychiatric unit over an eight-year period were retrospectively reviewed to determine the characteristics of patients with a discharge diagnosis of bipolar disorder. Forty-two patients had a diagnosis of an affective disorder, including 18 patients (nine males and nine females) with bipolar disorder. Mean age at onset of illness for patients with bipolar disorder was 15.7 years, and their onset of illness was likely to have been associated with psychotic symptoms. On admission, they were more likely to show symptoms of mania than of depression.