Psilocybin Therapy for Depression in Parkinson's Disease (PDP2)

May 29, 2026 updated by: Joshua Woolley, MD, PhD

The Efficacy of Psilocybin Therapy for Depression in Parkinson's Disease

The purpose of this study is to understand whether people with Parkinson's Disease and depression have improvement in their symptoms after psilocybin therapy.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

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.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
60

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Ellen Bradley, MD

Study Contact Backup

  • Name: Brigette Sosa
  • Phone Number: (415) 935-3489
  • Email: pdp2@ucsf.edu

Study Locations

  • United States
    • California
      • San Francisco, California, United States, 94143
        • Recruiting
        • University of California, San Francisco
        • Principal Investigator:
          • Joshua Woolley, MD,PhD
        • Sub-Investigator:
          • Ellen Bradley, MD
        • Contact:
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 40 to 80
  • Comfortable speaking and writing in English
  • Have neurologist-diagnosed idiopathic Parkinson's disease (PD), Hoehn and Yahr stages 1 to 3 during an "on" phase (time when medication/DBS for parkinsonian motor feature, including bradykinesia and rigidity is in effect)
  • Currently experiencing depressive symptoms
  • Able to attend all in-person visits at UCSF as well as virtual visits
  • Have a primary care provider, neurologist, or psychiatrist who is actively managing or coordinating

Exclusion Criteria:

  • Psychotic symptoms involving loss of insight
  • Significant cognitive impairment
  • Regular use of medications that may have problematic interactions with psilocybin
  • A health condition that makes this study unsafe or unfeasible, determined by study physicians

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Psilocybin Administration Session 1
Participants will receive one dose of psilocybin ranging from low ("microdose") to high and either pimavanserin or a placebo capsule in a medically monitored setting with preparation sessions before and integration sessions after.
Drug: Psilocybin
Single dose of psilocybin ranging from low ("microdose") to high delivered orally in two separate drug administration sessions with psychological support and monitoring.
Other Names:
  • 4-phosphoryloxy- N,N-dimethyltryptamine
Drug: Pimavanserin
Participants will receive either pimavanserin or placebo during their drug administration sessions.
Experimental: Psilocybin Administration Session 2
Participants will receive one dose of psilocybin ranging from low ("microdose") to high and either pimavanserin or a placebo capsule in a medically monitored setting with preparation sessions before and integration sessions after.
Drug: Psilocybin
Single dose of psilocybin ranging from low ("microdose") to high delivered orally in two separate drug administration sessions with psychological support and monitoring.
Other Names:
  • 4-phosphoryloxy- N,N-dimethyltryptamine
Drug: Pimavanserin
Participants will receive either pimavanserin or placebo during their drug administration sessions.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Evaluate the efficacy of psilocybin for improving depression in people living with Parkinson's disease
Time Frame: Baseline to 30 days after first drug dose
Changes in depression as measured by the MADRS
Baseline to 30 days after first drug dose

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Changes in depression severity
Time Frame: 7 days after first drug dose to 90 days after second drug dose
Measured by Beck Depression Inventory-2 (BDI-2) scores
7 days after first drug dose to 90 days after second drug dose
Changes in clinician-assessed depression
Time Frame: Baseline to 90 days after second drug dose
Measured by the Montgomery-Asberg Depression Rating Scale (MADRS)
Baseline to 90 days after second drug dose
Changes in anxiety
Time Frame: Baseline to 90 days after second drug dose
Measured by the Parkinson Anxiety Scale (PAS)
Baseline to 90 days after second drug dose
Changes in PD symptom severity
Time Frame: Baseline to 90 days after second drug dose
Measured by the Movement Disorder Society revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS)
Baseline to 90 days after second drug dose
Changes in Quality of Life
Time Frame: Baseline to 90 days after second drug dose
Measured by the 36-item Short Form survey (SF-36)
Baseline to 90 days after second drug dose
Changes in cognitive performance
Time Frame: Baseline to 90 days after second drug dose
Measured by a multi-task assessment
Baseline to 90 days after second drug dose
Safety and tolerability of psilocybin therapy for depression in people with PD
Time Frame: Baseline to 90 days after second drug dose
Incidence, severity, and frequency of Adverse Events (AEs) including Treatment-Emergent AEs (TEAEs) and Serious AEs (SAEs)
Baseline to 90 days after second drug dose
Changes in clinician-rated psychotic symptoms
Time Frame: Baseline to 90 days after second drug dose
Measured by the Enhanced Scale for the Assessment of Positive Symptoms for Parkinson's Disease (eSAPS-PD)
Baseline to 90 days after second drug dose
Subjective effects of psilocybin
Time Frame: Up to 30 and 60 days after Baseline
Measured by the 5-Dimensional Altered States of Consciousness Rating Scale (5D-ASC)
Up to 30 and 60 days after Baseline
Participant-reported acceptability of study procedures
Time Frame: 30 days after second drug dose
Measured by the study-specific Treatment Satisfaction Questionnaire-Participant (TSQ-P)
30 days after second drug dose

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Changes in peripheral inflammatory markers (exploratory)
Time Frame: Baseline to 90 days after second drug dose
Measured by blood-based analysis
Baseline to 90 days after second drug dose
Changes in participant reported sleep (exploratory)
Time Frame: Baseline to 90 days after second drug dose
Measured by the Parkinson's Disease Sleep Scale-2 (PDSS-2)
Baseline to 90 days after second drug dose
Changes in sleep parameters, physical activity, body temperature, and heart rate (exploratory)
Time Frame: Baseline to 30 days after first drug dose
Measured by using passive sensing via a wearable device
Baseline to 30 days after first drug dose
Evaluation of treatment expectations (exploratory)
Time Frame: Baseline
Measured by the Treatment Expectancy questionnaire consisting of 6 questions from the Stanford Expectations of Treatment Scale. Rating point scale is from 1 (Strongly disagree) to 7 (Strongly agree). Higher scores represent greater expectations of treatment benefit.
Baseline
Evaluation of masking procedures (exploratory)
Time Frame: Up to 30 and 60 days after Baseline
Measured by the study-specific Masking Questionnaire which includes items to assess perceived treatment assignment. Using a 7-point scale, higher scores represent greater certainty.
Up to 30 and 60 days after Baseline
Changes in brain structure and function (exploratory)
Time Frame: Baseline to 30 days after first drug dose
Measured by Positron Emission Tomography (PET) imaging, Magnetic Resonance Imaging (MRI) and Transcranial Magnetic Stimulation (TMS)
Baseline to 30 days after first drug dose

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Joshua Woolley, MD, PhD

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Joshua Woolley, MD,PhD, University of California, San Francisco
  • Principal Investigator: Ellen Bradley, MD, University of California, San Francisco

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
August 19, 2024

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 1, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 30, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 6, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 12, 2024

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 2, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 29, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • IRB#20-32641

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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