Major Affective Disorder as a Recurrent Illness

The systematic study of the natural course of affective disorders originated with the pioneer work of Kraepelin1and has continued until recently. However, with the advent of lithium and its widespread use in the prophylaxis of affective disorders, naturalistic data on the course of the illness has become increasingly unavailable. While reviewing the literature on the subject, one is struck by the discrepancies in the reported results and particularly the disparities concerning the proportion of patients with a single episode or those who experience several episodes during the observation period. It is our working assumption that methodological and population differences account for most, if not all, of the reported inconsistencies. For the purpose of this paper, we reviewed ten of the largest and most frequently quoted studies conducted over the past half century, largely in the predrug era, and concerning the natural course of affective illness. After presenting a