Revisiting Depressive-Prone Bipolar Disorder: Polarity of Initial Mood Episode and Disease Course Among Bipolar I Systematic Treatment Enhancement Program for Bipolar Disorder Participants

Background We examined the hypothesis that a first depressive rather than manic episode in bipolar disorder might herald a subsequent course notable for greater burden of depressive symptoms. Methods We analyzed retrospective data on the polarity of first mood episode obtained from 704 bipolar I subjects entering the multicenter Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) study. Subjects with an initial manic or depressive episode and those in whom both poles occurred within the same year were compared. Results Depressive-onset bipolar disorder was more common in women and those with earlier onset of illness. Adjusting for these differences, it was significantly associated with more lifetime depressive episodes and a greater proportion of time with depression and anxiety in the year prior to study entry. Conclusions Polarity of first mood episode may be useful in distinguishing subsets of bipolar patients at risk for a more chronic course.