Actively Recruiting
Elucidating the Relevance of the Psychedelic Experience to Psilocybin's Anti-Anhedonic Effects: A Randomized, Open-Label, Cross-Over fMRI Trial
Led by Medical University of Vienna · Updated on 2026-03-24
85
Participants Needed
1
Research Sites
N/A
Total Duration
On this page
Sponsors
M
Medical University of Vienna
Lead Sponsor
U
University of Vienna
Collaborating Sponsor
AI-Summary
What this Trial Is About
Researchers are investigating the potential effects of psilocybin on improving anhedonia, a condition characterized by reduced ability to experience pleasure, in patients with depression. This phase 1 clinical trial also explores how psilocybin influences brain activity during pleasurable experiences using advanced brain imaging techniques. The study compares psilocybin alone and combined with risperidone, a medication that blocks some psychedelic effects, to understand the role of the psychedelic experience in these outcomes. Participants receive two doses of 25 mg psilocybin orally in separate sessions. In one session, they also take 1 mg risperidone beforehand to block the psychedelic effects. The study uses a randomized, open-label, cross-over design where participants undergo psilocybin alone first or with risperidone first, followed by the other treatment in the second session. Additionally, participants have three MRI scans: one before treatment and one after each psilocybin session. During the study, participants complete various brain imaging tasks to assess changes in anhedonia, reward processing, and sexual arousal. They also complete questionnaires measuring well-being, depression, pleasure experiences, and resilience. Blood samples are taken to study inflammation and brain-related factors. The total participation includes follow-up assessments up to about 12 weeks after enrollment to monitor the effects and brain activity changes.
CONDITIONS
Brief Title
Elucidating the Relevance of the Psychedelic Experience to Psilocybin's Anti-Anhedonic Effects
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Age 18 to 55 years
- Right-handedness
- General good health based on medical history, physical exam, blood tests, and ECG
- Willingness and ability to sign informed consent
- Normal BMI range (18.5-24.9)
- For healthy subjects: no psychiatric diagnosis and no concomitant medication
- For anhedonia patients: diagnosis of major depressive episode with anhedonia by structured interview, no antidepressants or psychopharmaceuticals for at least 2 weeks (5 weeks for fluoxetine)
You will not qualify if you...
- Current or history of neurological disease
- Current medical illness requiring treatment
- Pregnancy or breastfeeding
- Current or past substance dependency
- Contraindications for MRI
- Failure to follow study protocol or instructions
- Female participants not confirming effective contraception at least 8 weeks before and after participation
- First-degree relative with bipolar disorder or schizophrenia
- For healthy subjects: any psychiatric diagnosis
- For anhedonia patients: psychiatric comorbidities except anxiety or obsessive-compulsive disorders
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 visit (in-person)
Duration - Up to 8 weeks
Participants receive two oral doses of psilocybin, one with and one without risperidone, in a randomized order with a cross-over design.
2 medication sessions and 3 MRI sessions
Duration - Up to 4 weeks after treatment
Participants complete follow-up assessments including questionnaires and biological measures to evaluate outcomes up to about 12 weeks after enrolment.
1 to 2 follow-up visits
Trial Site Locations
Total: 1 location
1
Medical University of Vienna, Department of Psychiatry and Psychotherapy, Division of General Psychiatry
Vienna, State of Vienna, Austria, 1160
Actively Recruiting
Research Team
M
Marie Spies, Priv.-Doz. DDr.
C
Clemens Schmidt, MD
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
RANDOMIZED
Model
CROSSOVER
Primary Purpose
TREATMENT
Number of Arms
2
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