RecruitingPhase 2Drug trialPsilocybin With Pimavanserin Compared to Psilocybin Alone for the Treatment of Major Depressive DisorderThis is an interventional, parallel arm assignment treatment study in individuals with Major Depressive Disorder (MDD). Each individual will be treated with a single dose of pimavanserin or placebo plus a single dose of psilocybin. Evaluations will be taken before dosing and following dosing at several timepoints up to 5 weeks post-dosing.