Indicators of Mania in Depressed Outpatients: A Retrospective Analysis of Data From the Kansas 1500 Study

Objective: Previous prospective studies have shown that unipolar depressed patients often switch to a manic episode. Some of these studies have reported that the conversion to bipolar disorder is predicted by an early onset of depression, a positive family history for mania, and psychotic symptoms. The present study examines the strength of the relationship between these 3 indicators, both alone and in combination, and the presence of mania in a large retrospective analysis.

Method: 1458 consecutive admissions to a large, Midwestern university outpatient clinic between 1981 and 1986 were interviewed, and 1002 patients met DSM-III inclusive criteria for major depressive disorder. Of these, information about age at onset of depression, family history of mania, and psychotic symptoms was available on 744 outpatients. Two structured interviews were used to assess the 3 indicators.

Results: In this large depressed outpatient sample, the incidence of lifetime mania was 27%. Each of the 3 indicators was significantly associated with the report of mania (p < .0001 for all 3 indicators). The rates of mania increased as the number of indicators increased. Psychotic symptoms were the strongest indicator, followed by a family history of mania and an early age at onset of depression.

Conclusion: Depressed patients with 1 or more of these 3 indicators should be monitored for the presence of bipolar disorder. Patients with 2 or more of these indicators are especially at risk to develop mania.