What does the evidence say about the efficacy of antidepressants?

The largest meta-analysis published by Cipriani et al. in 2018 demonstrated that all 21 antidepressants studied were more effective than placebo for treating major depressive disorder. The response rates ranged from approximately 40–60% for those on antidepressants, compared to 30–40% for placebo, indicating a real but modest absolute difference of 15–20% more patients improving on antidepressants.