Residual symptoms at remission from depression: impact on long-term outcome

Background: Although residual symptoms after remission from depression are common and predict early relapse, little is known about the impact of residual symptoms on longer-term clinical course of depression or social functioning. Methods: Sixty severe recurrent depressives, who remitted from an index episode of depression with residual symptoms or below residual symptomatology, were followed-up at 8–10 years. Subjects underwent detailed longitudinal interviewing on course of depression, treatment and socioecomonic functioning over follow-up. Results: Long-term follow-up data was obtained on all living subjects and 55 (95%) were interviewed. The residual symptoms group spent more time with depressive symptoms over follow-up but not at full criteria for major depression and showed greater impairment in longitudinal and follow-up social adjustment. No significant differences were found between the two groups in percentage recurring long-term, mean number of recurrences, readmissions, chronic episodes or clinical global outcome criteria. Limitations: Long-term clinical and social outcomes were assessed by a single retrospective longitudinal interview. Conclusions: Patients who remit from depression with residual symptomatology continue to have more depressive symptoms and impaired social functioning long-term and may need more aggressive treatment.