Association between duration of antidepressant treatment for major depressive disorder and relapse rate after discontinuation: a meta-analysis

The optimal duration of antidepressant treatment for patients with major depressive disorder to reduce the risk of relapse after discontinuation remains uncertain. Medline, Cochrane Central Register of Controlled Trials, and Embase were systematically searched for randomized controlled trials (RCTs) with a discontinuation design. A single-group summary meta-analysis was performed to calculate 6-month relapse rates after discontinuation. Meta-regression with restricted cubic splines was performed to model the non-linear relationship between treatment duration and relapse rate after discontinuation. Thirty-five RCTs were included. The relapse rate after discontinuation was approximately 34.81% at 6 months and 45.12% at 12 months. After controlling for covariates, the meta-analysis shows that the duration of treatment is associated with the risk of relapse after discontinuation in a non-linear curve, with a relatively higher risk of relapse observed for a duration of less than three months. There appears to be no further reduction in the risk of relapse when treatment is continued for over six months. Our results indicate the importance of at least three months of treatment to avoid the relatively high risk of relapse after discontinuation. The additional benefit of longer treatment remains to be proven.