Recruiting
Phase 2

Psilocybin

Sponsor:

Robin Carhart-Harris, PhD, MA

Code:

NCT06626139

Conditions

Healthy Participants With Lower-than-average Mental Well-being

Eligibility Criteria

Sex: All

Age: 21 - 70

Healthy Volunteers: Accepted

Interventions

Psilocybin

Context 1

Context 2

Placebo

Study Details

Brief summary:

One hundred twenty healthy participants, ages 21 to 70, who experience moderate-to-lower-than-average mental well-being will be evenly randomized into four different study arms, using a 2x2 factorial design. Depending on the study arm, participants will either receive an inactive placebo or up to 25mg psilocybin (oral dose), in one of two set and setting conditions; drug administration contexts that are predicted to modulate drug effects.

The purpose of this study is to evaluate any interaction effects between an oral dose of psilocybin and the surrounding context (set and setting).

Conditions

Healthy Participants With Lower-than-average Mental Well-being

Study ID

NCT06626139

Start date

Oct 20, 2024

Status verified date

Jun, 2026

Completion date

Nov 30, 2028

Anticipated

Primary completion date

Nov 30, 2027

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 21 - 70

Healthy Volunteers: Accepted

If you are interested in participating in this study, please follow this link to check your eligibility: https://tiny.ucsf.edu/setsettingscreener

Inclusion Criteria:

Participants will be considered for inclusion if they:

1. Are between 21 and 70 years of age
2. Are fluent in speaking and reading English
3. Are able to swallow pills/capsules
4. If able to become pregnant, must be non-lactating, have a negative pregnancy test at study entry and prior to each Experimental Session and must agree to an adequate form of birth control over the course of the study. Adequate forms of birth control include intrauterine device (IUD), injected, implanted, intravaginal, or transdermal hormonal methods, abstinence, oral hormones plus a barrier contraception, vasectomized sole partner, or double barrier contraception. Two forms of contraception are required with any barrier method or oral hormones (i.e., condom plus diaphragm, condom or diaphragm plus spermicide, oral hormonal contraceptives plus spermicide or condom). Unable to become pregnant is defined as documented hysterectomy, bilateral salpingectomy, bilateral oophorectomy, and/or tubal ligation), permanently sterile by medical device such as Essure, postmenopausal, or assigned male sex at birth.
5. Able and willing to provide informed consent
6. Able and willing to use computers and tablets or phones to enter electronic data
7. Agree to inform the investigators within 48 hours of any new or changed medical conditions.
8. Have an identified support person
9. For those dosed with psilocybin, their prior consent to be accompanied home (or to an otherwise safe destination) by a support person, chosen by them - ahead of time, or by a member of the study team.
10. Willing to provide contact details for a friend or family member, should there be an inability to make direct contact with the participant

Exclusion Criteria:

Participants will be excluded if they:

1. Have a current diagnosed psychiatric disorder that, in the opinion of the study clinician or PI, renders to person psychologically unstable or unduly vulnerable, or interferes with activities of daily living, or could impact attendance at or participation in study activities
2. Have a medically significant condition that renders the person unsuitable for the study
3. Give a positive alcohol breathalyzer test result on any study visit
4. A positive urine drug screen to any excluded substances prior to an Experimental Session, which warrants exclusion based on concerns that it may compromise safety or confound outcomes
5. Are breastfeeding, or have a positive pregnancy test at screening or at any point during the course of the study
6. Systolic and diastolic BP values exceeding 139 SBP and exceeding 89 DBP and heart rate exceeding 90 bpm would result in exclusion from the study.
7. Present with a exceeding 450 msec or with evidence of cardiac damage, ischemia, or heart disease.
8. Have received an investigational drug within 30 days of the screening visit
9. Have an allergy or intolerance to any of the materials contained in either drug product or setting components, such as certain scents.
10. Have MRI contraindications (e.g., metal implants, pacemakers, claustrophobia etc.)
11. Have any current problem which, in the opinion of the investigator or clinician, might interfere with participation.

Study Design

Enrollment

120 participants

Anticipated

Allocation

Randomized

Intervention Model

Factorial

Primary purpose

Basic Science

Interventions and Outcome Measures

Arms

experimental: Psilocybin C1

Following screening and a baseline assessment visit, healthy volunteers will receive one dose of up to 25mg psilocybin in a context (Context 1) that is hypothesized to modulate acute and post-acute drug effects.

experimental: Psilocybin C2

Following screening and a baseline assessment visit, healthy volunteers will receive one dose of up to 25mg psilocybin in a context (Context 2) that is hypothesized to modulate acute and post-acute drug effects.

placebo comparator: Placebo C1

Following screening and a baseline assessment visit, healthy volunteers will receive one dose of an inactive placebo in a context (Context 1) that is hypothesized to modulate acute and post-acute drug effects.

placebo comparator: Placebo C2

Following screening and a baseline assessment visit, healthy volunteers will receive one dose of an inactive placebo in a context (Context 2) that is hypothesized to modulate acute and post-acute drug effects.

Interventions

Psilocybin

Healthy participants will receive up to 25 mg psilocybin.

Context 1

Drug administration will take place in a context (Context 1) that is expected to modulate acute and post-acute drug effects.

Context 2

Drug administration will take place in a context (Context 2) that is expected to modulate acute and post-acute drug effects.

Placebo

Healthy participants will receive an inactive placebo.

Primary outcome measure

  • Challenging Experience Questionnaire (CEQ) subscales score [ Time Frame: Eight hours post-dose. ]
  • Change in Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS) score from Baseline to 28 days post-dose [ Time Frame: Baseline to 28 days post-dose. ]
  • Change in Watts Connectedness Scale (WCS) scores from Baseline to 28 days post-dose [ Time Frame: Baseline to 28 days post-dose. ]
  • Emotional Breakthrough Inventory (EBI) score [ Time Frame: Eight hours post-dose. ]

Central Contacts and Locations

Central contacts

Avery Ostrand, MSc

avery.ostrand@ucsf.edu

Locations

UCSF Mission Bay

Recruiting

San Francisco, California, United States, 94158

Contacts

More Information

Sponsor

Robin Carhart-Harris, PhD, MA

Last update posted

Jun 4, 2026

Last verified

Jun, 2026

Keywords

  • well-being
  • psilocybin
  • psychedelic
  • neuroimaging
  • healthy volunteers

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Robin Carhart-Harris, PhD, MA on 2026-06-04.