RECOVERY FROM MAJOR DEPRESSION - A 10-YEAR PROSPECTIVE FOLLOW-UP ACROSS MULTIPLE EPISODES

Background: Major depressive disorder is often marked by repeated epis odes of depression. We describe recovery from major depession across m ultiple mood episodes in patients with unipolar major depression at in take and examine the association of sociodemographic and clinical vari ables with duration of illness. Methods: A cohort of 258 subjects trea ted for unipolar major depressive disorder was followed up prospective ly for 10 years as part of the Collaborative Depression Study, a multi center naturalistic study of the mood disorders. Diagnoses were made a ccording to the Research Diagnostic Criteria, and the course of illnes s was assessed with the Longitudinal Interval Follow-up Evaluation. Su rvival analyses were used to calculate the duration of illness for the first 5 recurrent mood episodes after recovery from the index episode . Results: Diagnosis remained unipolar major depressive disorder for 2 35 subjects (91%). The median duration of illness was 22 weeks for the first recurrent mood episode, 20 weeks for the second, 21 weeks for t he third, and 19 weeks for the fourth and fifth recurrent mood episode s; the 95% confidence intervals were highly consistent. From one episo de to the next, the proportion of subjects who recovered by any one ti me point was similar. For subjects with 2 or more recoveries, the cons istency of duration of illness from one recovery to the next was low t o moderate. None of the sociodemographic or clinical variables consist ently predicted duration of illness. Conclusion: In this sample of pat ients treated at tertiary care centers for major depressive disorder, the duration of recurrent mood episodes was relatively uniform. and av eraged approximately 20 weeks.