Pilot Study on the Effects of Psilocybin on Belief Updating and Insight Formation
The primary aim of this phase I mechanistic pilot study is to evaluate the effects of psilocybin on aspects of cognition in healthy adult volunteers. Up to 24 participants will receive a single dose of either psilocybin or inert placebo, and they will be asked to complete several computer-based behavioral tasks measuring features of learning, belief updating, and abstraction. (The sponsor's summary, shortened.)
Eligibility and contacts on ClinicalTrials.govThe registry record
- Status
- Recruiting
- Phase
- Phase 1
- Conditions
- Phase I
- Intervention
- Psilocybin (Usona Institute); Inactive Placebo (Usona Institute)
- Sponsor
- Brown University
- Ages
- 18 Years and over
- Sex
- All
- Healthy volunteers
- Accepted
- Enrolment
- 24 people (planned)
- Start
- November 2026
- Primary completion
- November 2027
- Registry last updated
- 8 October 2026
Sites (1)
- Brown University School of Public Health, Providence, Rhode Island, United States (recruiting)
How joining a trial works
- Free to take part
- Trials generally cost participants nothing for the study drug and the study visits, and some pay for travel or time. Check what a study covers on its registry page.
- Screened first
- Every study screens volunteers with questionnaires, medical history and often a physical and psychiatric check. Many people who apply are not enrolled.
- Eligibility is strict
- Common exclusions include a personal or family history of psychosis or bipolar disorder, some heart conditions, pregnancy and certain medications, which you may be asked to stop under medical supervision. Never stop a medication on your own to qualify.
- You may get a placebo
- Many trials compare psilocybin with a placebo or a low dose, and you may not be told which you had until the study ends.
- Contact the study team through the registry
- Each registry record lists the study contacts and sites. We do not republish personal emails or phone numbers; use the link on each trial page.
- Not medical advice
- This is a list of registry records, not a recommendation. Talk to your doctor before applying. Disclaimer · Safety and medications
Source: ClinicalTrials.gov API v2, U.S. National Library of Medicine, read 28 October 2026. Filter: overall status RECRUITING or NOT_YET_RECRUITING; an intervention named psilocybin, psilocin, COMP360 or CYB003. Refreshed weekly; a study's own registry page is always the current record.
Record read from ClinicalTrials.gov API v2, U.S. National Library of Medicine on 28 October 2026. All psilocybin trials