Psilocybin for Major Depressive Disorder (MDD)

Approximately 240 eligible adult participants (≥18 years old) who meet Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR) criteria for Major Depressive Disorder (MDD) will be enrolled. Participants will be randomly assigned to receive a single oral dose of Psilocybin 25 mg, Psilocybin 5 mg, or inactive placebo. The purpose of this study is to evaluate the efficacy, safety, and tolerability of Psilocybin 25 mg versus placebo in adults with MDD, as assessed by the difference between groups in change in depressive symptoms from Baseline to Day 43 post-dose, and to characterize the durability of initial treatment effect and subsequent response to optional Psilocybin 25 mg re-administration(s) during the 1-year Follow-up Period.