Abstract
Onset of mania was evaluated retrospectively in 48 bipolar manic-depressive patients. Mania occurred as the initial episode in 40% of cases. In patients with initial episode of depression, approximately 80% developed mania prior to their third episode of depression and within 5 years from the onset of this illness. Differences in type of illness onset were related to family history of bipolar illness and sex of the proband. Male patients with a positive family history were significantly more likely to manifest mania at onset of illness.