Actively Recruiting
Elucidating the Relevance of the Psychedelic Experience to Psilocybin's Anti-Anhedonic Effects
Led by Medical University of Vienna · Updated on 2026-03-24
85
Participants Needed
1
Research Sites
134 weeks
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
The goal of this clinical trial is to systematically categorize potential prohedonic effects of psilocybin in patients with anhedonia in depression. The main questions it aims to answer are: Primary Objectives 1. Systematically categorize prohedonic effects (antianhedonic effects in patients with anhedonia in depression, increase in well-being in all participants). 2. Test effects of psilocybin on brain network complexity measures during the hedonic experience using fMRI as a correlate for prohedonic (anti-anhedonic and well-being increasing) effects. 3. Elucidate relevance of the psychedelic experience to these effects (clinical, behavioral, and imaging) in a pharmacological challenge using the 5-HT2A/D2 antagonist risperidone and extensive characterization of the psychedelic experience. Secondary Objectives 4. Test the differential effects of the psychedelic experience on fMRI paradigms measuring symptoms shown to be altered in anhedonia, more specifically reward processing and sexual arousal. 5. Test the relevance of neuroplasticity (BDNF) and inflammatory parameters to anti-anhedonic, well-being promoting, and brain network dynamic complexity effects. 6. Test the effects of the psychedelic experience on BDNF and inflammatory parameters. Researchers will compare the effects of psilocybin in two separate sessions (one with psilocybin alone, one with co-administration of risperidone) in both patients with depression and anhedonia and healthy control participants. Participants will: * Take 25 mg of psilocybin p.o. in two sessions, in one of the two sessions they will take 1 mg risperidone p.o. before ingestion of psilocybin, to block psilocybin's acute psychedelic effects. * Undergo 3 MRI sessions, one before the first psilocybin session ('baseline') and one session each on the day after each respective psilocybin session. * Perform a variety of tasks during each fMRI session to asses the treatment's effects on anhedonia.
CONDITIONS
Official 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-handed
- Normal body weight (BMI 18.5-24.9)
- General good health based on medical history, physical exam, blood tests, and ECG
- Willing and able to sign informed consent
- For healthy participants: no psychiatric diagnosis and no current medications
- For anhedonia patients: diagnosed major depressive episode with anhedonia, no psychopharmaceuticals (including antidepressants) for at least 2 weeks (5 weeks for fluoxetine)
You will not qualify if you...
- Current or past neurological diseases
- Current medical illness requiring treatment
- Pregnancy or breastfeeding
- Current or past substance dependency
- Any reason preventing MRI scanning
- Inability to follow study procedures
- Female participants not confirming effective contraception use 8 weeks before and after study
- First-degree relative with bipolar disorder or schizophrenia
- For healthy participants: any psychiatric diagnosis
- For anhedonia patients: psychiatric disorders other than anxiety or obsessive-compulsive disorders
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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.
CONTACT
C
Clemens Schmidt, MD
CONTACT
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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