Cancer Related Major Depression Treated With a Single Dose of Psilocybin (CAPSI)

This randomised, parallel‑group, quadruple‑blind study randomises participants 2:1 to a single oral 25 mg dose of psilocybin or an active placebo (1 mg) to evaluate antidepressant efficacy in cancer‑related major depressive disorder.

Primary outcome is change in depressive symptoms; participants undergo preparatory and follow‑up sessions, safety monitoring including ECG and labs, and must abstain from other psychotherapies or antidepressants during the study period.