The prospective long-term course of adult depression in general practice and the community. A systematic literature review

BackgroundFindings about the prospective long-term course of depression are usually derived from clinical populations while knowledge about the course in community and primary care samples is rarer. As depressive disorders are highly prevalent and associated with considerable disability and costs, this information is needed to identify the percentages of subjects with a favorable or unfavorable prognosis. Therefore our aim was to summarize the available evidence on the prospective longitudinal course of depression in both general practice and the community.MethodsWe conducted a systematic, computerized search of Medline and PsycINFO. Main selection criteria were (a) adults with observer assessed depressive disorder recruited in the community or in general practice and (b) naturalistic study with follow-up length of at least three years. As primary outcome the percentages of stable recovery, recovery during or at follow-up, recurrence and chronic course were used.ResultsWe identified 12 cohorts, with 4009 followed-up individuals. Follow-up intervals ranged between three and 49 years. Between 35% and 60% of participants experienced a stable recovery with no (further) recurrences, while 70-85% recovered at least once during follow-up. A consistent percentage of 10-17% had a chronic course. Recurrence rates varied considerably ranging between 7% and 65%. Significant predictors of an unfavorable course appear to be mainly those variables that lie within the course of depression itself, i.e. history of depression, baseline severity, and comorbidity.LimitationsUse of broad inclusion criteria heightened study heterogeneity and hampered comparability.ConclusionRegarding stable recovery, the long-term course within general practice and community samples seems more favorable than within clinical samples. Further research applying a standardized methodology is required.