Season and manic relapse.

The episodes of mania occurring in a cohort of 86 patients with bipolar affective disorder were recorded over a 6-year period. Of the 54 patients who had at least 2 episodes, 8 (15%) met our criteria for a seasonal pattern of relapse. There was no particular season in which these relapses clustered. Overall, the time of year of the first recorded episode during the 6-year period did not predict the timing of subsequent episodes.