The effect of psilocybin on major depressive disorder (MDD) symptom severity and synaptic density - a single dose randomized, double blind, placebo-controlled Phase IIb positron emission tomography study.
Randomized, double-blind, parallel-group Phase 2b trial (n=35 actual) comparing a single 25 mg oral dose of psilocybin with a single 100 mg niacin active placebo in adults with MDD; primary outcome is change in MADRS score to Day 8.
Participants undergo MRI and PET with [11C]UCB-J to assess synaptic density at baseline and Day 15; one preparation session and three post-dose integration sessions are provided under a set-and-setting protocol with two facilitators present during dosing.
Safety measures and biological samples (CSF, blood) collected at baseline and Day 15; follow-up visits continue to Day 365 for clinical outcomes and safety.
Single oral 25 mg psilocybin dose
Single oral 100 mg niacin active placebo
Niacin 100 mg active placebo to aid blinding