Psilocybin Therapy for Depression and Anxiety in Parkinson's Disease

This is an open-label single-arm pilot study of oral psilocybin therapy for depression and anxiety in people with Parkinson's Disease (PD). The primary goal is to examine safety, tolerability, and feasibility of the intervention in this patient population. We will enroll people ages 40 to 75 with clinically diagnosed early stage Parkinson's Disease (Hoehn and Yahr Stage 1-3 during an "off" period), who meet DSM-5 criteria for a depressive or anxious disorder and meet all other inclusion and exclusion criteria at screening. After baseline assessments, participants will complete preparation sessions designed to provide information about the psilocybin experience and to build rapport/trust with the study team. Next, participants will complete a first psilocybin administration session, receiving a low-moderate dose of 10 mg oral psilocybin in a supervised setting with safety monitoring by a physician. Participants who do not experience significant adverse events during or following the session will complete a second psilocybin administration session approximately two weeks later. During the second psilocybin administration session, participants will receive a moderate-high dose of 25 mg oral. The second session will involve the same procedures and level of monitoring as the first. Participants will subsequently complete multiple follow-up sessions designed to assess PD and psychiatric symptoms as well as to provide support as they process their psilocybin experiences. Follow-up will continue to 3 months after the second psilocybin administration session. Primary endpoints will assess safety, tolerability, and feasibility of study procedures. Exploratory efficacy endpoints will assess changes in depressive symptoms, anxious symptoms, and related measures of function.