Psilocybin Therapy for Depression in Parkinson's Disease

This is a randomized controlled trial of oral psilocybin therapy for depression in people with Parkinson's disease (PD). The primary goal is to examine efficacy of psilocybin therapy in this patient population. We will enroll 60 people ages 40 to 80 with clinically diagnosed early to moderate stage Parkinson's disease (Hoehn and Yahr Stage 1-3 during an "on" period), who meet criteria for moderate or greater depression severity and meet all other inclusion and exclusion criteria at screening. Participants will complete two drug administration sessions where they will each receive a dose of oral psilocybin ranging from low ("microdose") to high in a medically monitored setting with psychotherapeutic support. Participants will also complete a series of psychotherapy sessions before and after each drug administration session. Clinical assessments, neuroimaging, non-invasive brain stimulation, and peripheral blood draws will be used to quantify changes in depression, other non-motor and motor symptoms of PD, quality of life, and selected neural and blood-based biomarkers at multiple time points. Follow-up will continue to 3 months after the second session. Primary endpoints will evaluate efficacy, safety, and tolerability of study procedures. After posting of these trial results, this data will be combined with the data from the trial at Yale University (NCT07610369) for publication purposes.