What is the short-term remission rate for people with untreated depression? A systematic review and meta-analysis.

BACKGROUND: Depression is one of the prevalent mental illnesses and leading cause of global disease burden. However, most people with depression do not access treatment. Remission without treatment may occur in some cases of depression. This study aimed to estimate the short-term remission (natural recovery) from untreated depression. METHODS: A systematic review and meta-analysis was registered on PROSPERO and conducted following PRISMA guidelines. EMBASE, PsycINFO, and PubMed were searched, supplemented with an additional hand search to identify studies reporting natural recovery from untreated depression. Study selection and screening were carried out by three independent reviewers. Methodological quality assessment of the included studies was conducted. Remission was defined as no longer meeting the diagnostic criteria or scoring below the cut off points of the validated tools as reported by the included studies. The data were synthesized using narrative summary and random-effects meta-analysis. RESULTS: Sixteen waitlist-controlled trial studies were included in the systematic review and meta-analysis. The duration of follow-up ranged from 4 to 12 weeks with a median duration of 8 weeks. The overall pooled remission from untreated depression was 12.5%, 95% confidence interval (7.8, 18.0%). Due to lack of published data, we were unable to determine if the severity of depression symptoms was associated with remission rates. CONCLUSIONS: Short-term remission from depression without treatment is uncommon. Across studies, 8 - 18% of people remitted without treatment within 12 weeks. Waitlist control groups may not represent all persons with depression.