Effects of Psilocybin With Psychological Support on Anhedonia in Treatment-resistant Depression: a Randomized Controlled Pilot Trial

This Phase II randomised, quadruple‑blind, parallel study evaluates whether a single 25 mg oral dose of psilocybin plus psychological support reduces anhedonia in participants with treatment‑resistant major depressive disorder compared with an ultra‑low (1 mg) active‑placebo.

Primary efficacy is measured with MADRS (including item 8 for interest/ability to feel); secondary assessments include safety labs, ECG, adverse events, and neuroimaging (fMRI) outcomes. Psychological support is provided pre, during and post dosing.