Relation of age at onset to duration of episode in unipolar depression

The purpose of this study was to test the hypothesis that the duration of episodes of unipolar depression increases with age at onset. On the basis of elevated scores on a self-report depression measure, 2,020 persons were selected from a larger community sample to be interviewed and diagnosed using the Schedule for Affective Disorders and Schizophrenia-Research Diagnostic Criteria procedures. Of the 2,020 persons, 865 had a history of one or more episodes of unipolar depression. The potential effects of the following variables (singly and in interaction) on duration of episode were assessed by means of multiway frequency table analysis and chi-square: age at onset, sex of subject, interval since occurrence of the episode, and type of disorder (major vs. minor depressive disorder). The hypothesis that duration of episodes of depression increases with age at onset was not supported. Women were more likely to have multiple episodes, but did not have longer lasting episodes.