INTRODUCTION: Social functioning (SF) is the ability to fulfil one's social obligations and a key outcome in treatment.

OBJECTIVE: The aim of the study was to estimate the effects of antidepressants on SF in patients with major depressive disorder (MDD).

METHODS: This meta-analysis and its reporting are based on Cochrane Collaboration's Handbook of Systematic Reviews and Meta-Analyses and PRISMA guidelines (protocol registration at OSF). We systematically searched CENTRAL, Medline, PubMed Central, and PsycINFO for double-blind RCTs comparing antidepressants with placebo and reporting on SF. We computed standardized mean differences (SMDs) with 95% CIs and prediction intervals.

RESULTS: We selected 40 RCTs out of 1,188 records screened, including 16,586 patients (mean age 46.8 years, 64.2% women). In 27 studies investigating patients with MDD (primary depression), antidepressants resulted in a SMD of 0.25 compared to placebo ([95% CI: 0.21; 0.30] I2: 39%). In 13 trials with patients suffering from MDD comorbid with physical conditions or disorders, the summary estimate was 0.24 ([0.10; 0.37] I2: 75%). In comorbid depression, studies with high/uncertain risk of bias had higher SMDs than low-risk studies: 0.29 [0.13; 0.44] versus 0.04 [-0.16; 0.24]; no such effect was evident in primary depression. There was no indication of sizeable reporting bias. SF efficacy correlated with efficacy on depression scores, Spearman's rho 0.67 (p < 0.001), and QoL, 0.63 (p < 0.001).

CONCLUSIONS: The effect of antidepressants on SF is small, similar to its effect on depressive symptoms in primary MDD, and doubtful in comorbid depression. Strong correlations with both antidepressive and QoL effects suggest overlap among domains.