The purpose of this guidance is to assist sponsors in the clinical development of drugs for the monotherapeutic, combination, and adjunctive treatment of major depressive disorder (MDD). Specifically, this guidance addresses the FDA’s current thinking regarding the overall development program and clinical trial designs for antidepressant drug products. This draft guidance is intended to serve as a focus for continued discussions among the Division of Psychiatry Products (the Division), pharmaceutical sponsors, the academic community, and the public.