Effects of Repeated Psilocybin Dosing in OCD

NCT ID: NCT05370911

Last Updated: 2025-07-10

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Clinical Phase

PHASE1

Total Enrollment

30 participants

Study Classification

INTERVENTIONAL

Study Start Date

2023-07-20

Study Completion Date

2027-07-31

Brief Summary

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This study aims to investigate the effects of repeated dosing of oral psilocybin on obsessive-compulsive disorder (OCD) symptomatology in a randomized, waitlist-controlled design with blinded independent ratings, and assess psychological mechanisms that may mediate psilocybin's therapeutic effects on OCD.

Detailed Description

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Aim 1: To examine the effects of two doses of psilocybin on OCD symptoms among participants in the immediate treatment condition, compared to participants in the waitlist control/delayed treatment condition. The investigators hypothesize that participants in the immediate treatment group will report statistically significantly greater symptom improvement from baseline 4 days post-second dose, compared to participants in the waitlist control/delayed treatment group at the same interval during their waitlist phase.

Aim 2: To examine the effects of two doses of psilocybin on OCD symptoms, compared to one dose. The investigators hypothesize that two doses of oral psilocybin will reduce OCD symptoms to a statistically significantly greater extent than one dose.

This study aims to investigate the effects of repeated dosing of oral psilocybin on OCD symptomatology and assess psychological mechanisms that may mediate psilocybin's therapeutic effects on OCD. This study will employ a randomized, waitlist-controlled design with blinded independent ratings, with participants randomized to receive either immediate treatment (two doses oral psilocybin separated by one week) or delayed treatment (7 weeks post-randomization). An adaptive dose selection strategy will be implemented, with the first dose being standardized at 25 mg of psilocybin, and the second dose being either the same or a higher dosage (i.e., 30 mg) on the basis of a clinically significant response from baseline or not, respectively, 4 days post-first dose.

This study is conducted entirely on an outpatient basis with the possibility of remote/virtual follow-up visits after each dosing session. The dosing sessions last the entire day, and participants will be medically cleared prior to being permitted to return home with assistance (e.g., driven by a family member or friend, or ride share).

Conditions

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Obsessive-Compulsive Disorder

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

In the study, participants will be randomized to receive either immediate treatment with two doses of oral psilocybin separated by one week (n = 15) or enter a waitlist control/delayed treatment group and receive the same treatment 7 weeks post-randomization (n = 15).
Primary Study Purpose

TREATMENT

Blinding Strategy

SINGLE

Outcome Assessors
Only the independent rater for each participant will be blinded to their condition; blind will be broken at the end of week 7 (i.e., 4 weeks post-second dosing), after which participants in the waitlist/delayed treatment group will begin their treatment phase.

Study Groups

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Immediate Treatment

Participants randomized to this condition will receive treatment immediately, facilitated by two study staff members, and which consists of two preparatory sessions, followed by the first dosing session and two integration sessions, then the second dosing session and two integration sessions. This is followed by follow-up and long-term follow-up visits up to 12 months post-second dose.

Group Type EXPERIMENTAL

Psilocybin

Intervention Type DRUG

The first oral dose will be 25 mg, and the second dose will be either 25 mg or 30 mg, depending on response to first dose.

Psilocybin is a naturally occurring hallucinogenic ingredient found in some varieties of mushrooms that can be produced synthetically. It is considered to be a serotonergic psychedelic. We will use synthetically produced oral psilocybin in this study.

Other Names:

"Magic Mushrooms"

Waitlist Control/Delayed Treatment

Participants randomized to this condition will first enter a waitlist phase that lasts for 7 weeks, after which rater unblinding will occur, and participants will be rescreened. If participants remain eligible at this time, they will begin their treatment phase. During their treatment phase, participants in this condition will receive the same treatment as described for participants in the immediate treatment group. This is followed by follow-up and long-term follow-up visits up to 12 months post-second dose.

Group Type NO_INTERVENTION

No interventions assigned to this group

Interventions

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Psilocybin

The first oral dose will be 25 mg, and the second dose will be either 25 mg or 30 mg, depending on response to first dose.

Psilocybin is a naturally occurring hallucinogenic ingredient found in some varieties of mushrooms that can be produced synthetically. It is considered to be a serotonergic psychedelic. We will use synthetically produced oral psilocybin in this study.

Other Names:

"Magic Mushrooms"

Intervention Type DRUG

Eligibility Criteria

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Inclusion Criteria

1. Primary DSM-5 diagnosis of OCD, with Y-BOCS-II score of 26 or greater at screening
2. Failed at least one medication and/or therapy trial of standard care treatment for OCD
3. English fluency
4. Agree to sign a medical release for investigators to communicate directly with participants' providers to confirm medication and psychotherapy histories or arrange contingencies in event of crises.
5. Agree to provide an adult contact (relative, spouse, close friend or other caregiver) who is willing and able to be reached by the PI and/or study personnel in the event of an emergency, and who can provide transportation for study visits and independently comment on any changes in the participant's mood or behavior after each administration of psilocybin.
6. Agree to commit to all study procedures.
7. Ability to orally ingest pills for psilocybin dosing visits.
8. Agree to adhere to lifestyle and medication modifications.
9. Must not be on psychotropic medications for OCD or comorbid psychiatric conditions for at least 8 weeks at the time of randomization, and agree to refrain from taking or starting any psychiatric medications until after 4 weeks post-second dose.
10. Must not be in current psychotherapy (CBT or ERP) and must not start new course of psychotherapy (CBT or ERP) for OCD or comorbid psychiatric conditions until after 4 weeks post-second dose.
11. If participant is of childbearing potential, must have a negative pregnancy test at study entry and prior to each dosing session.
12. If participant is of childbearing potential, agree to use adequate birth control and not attempt to become pregnant during study up to 4 weeks post-second dose.

Exclusion Criteria

1. Personal or immediate (first-degree relative) family history of formally diagnosed schizophrenia or other psychotic disorders, or bipolar I/II disorder
2. Lack of knowledge about biological families' medical history, due to adoption or other circumstance
3. Active suicidal intent or suicidal or non-suicidal self-injurious behaviors
4. Unremitted Tourette syndrome
5. Lifetime diagnosis of autism spectrum disorder
6. Current substance use disorder (except for mild alcohol use disorder)
7. Any neurological condition, including history of seizure(s) or chronic/severe headaches
8. Any history of head injury with loss of consciousness for more than 30 min
9. Any use of classic psychedelic substances within the prior 12 months
10. Unwillingness to abstain from use of classic psychedelics outside of the study up to 4 weeks post-second dose.
11. Use of tobacco products or a THC-containing product more than 2 times per week on average over the past 30 days at screening.
12. Unwilingness or inability to abstain from use of tobacco or THC-containing products from 1 week prior to randomization up to 4 weeks post-second dose.
13. Positive urine drug test for any prohibited substance at screening or days of dosing, or positive breathalyzer test for alcohol on days of dosing
14. Unwillingness or inability to abstain from alcohol use at least 24 hours prior to the days of dosing, up to 24 hours after each dosing day (or corresponding intervals for waitlist group).
15. Any medical conditions that may render study procedures unsafe, including hypertension, history of cardiovascular disease, moderate-to-severe hepatic or renal impairment, diabetes, and hypo- or hyperthyroidism.
Minimum Eligible Age

18 Years

Maximum Eligible Age

65 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Steven & Alexandra Cohen Foundation

OTHER

Sponsor Role collaborator

Yale University

OTHER

Sponsor Role lead

Responsible Party

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Benjamin Kelmendi, MD

Assistant Professor of Psychiatry

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Benjamin Kelmendi, MD

Role: PRINCIPAL_INVESTIGATOR

Yale University

Terence Ching, PhD

Role: PRINCIPAL_INVESTIGATOR

Yale University

Christopher Pittenger, MD, PhD

Role: STUDY_DIRECTOR

Yale University

Locations

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Yale OCD Research Clinic (40 Temple St, 4th Floor)

New Haven, Connecticut, United States

Site Status RECRUITING

Countries

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United States

Central Contacts

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Terence Ching, PhD

Role: CONTACT

(203) 974-7731

Facility Contacts

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Terence Ching, PhD

Role: primary

(203) 974-7731

References

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Moreno FA, Wiegand CB, Taitano EK, Delgado PL. Safety, tolerability, and efficacy of psilocybin in 9 patients with obsessive-compulsive disorder. J Clin Psychiatry. 2006 Nov;67(11):1735-40. doi: 10.4088/jcp.v67n1110.

Reference Type BACKGROUND
PMID: 17196053 (View on PubMed)

Davis AK, Barrett FS, May DG, Cosimano MP, Sepeda ND, Johnson MW, Finan PH, Griffiths RR. Effects of Psilocybin-Assisted Therapy on Major Depressive Disorder: A Randomized Clinical Trial. JAMA Psychiatry. 2021 May 1;78(5):481-489. doi: 10.1001/jamapsychiatry.2020.3285.

Reference Type BACKGROUND
PMID: 33146667 (View on PubMed)

Ross S, Bossis A, Guss J, Agin-Liebes G, Malone T, Cohen B, Mennenga SE, Belser A, Kalliontzi K, Babb J, Su Z, Corby P, Schmidt BL. Rapid and sustained symptom reduction following psilocybin treatment for anxiety and depression in patients with life-threatening cancer: a randomized controlled trial. J Psychopharmacol. 2016 Dec;30(12):1165-1180. doi: 10.1177/0269881116675512.

Reference Type BACKGROUND
PMID: 27909164 (View on PubMed)

Griffiths RR, Johnson MW, Carducci MA, Umbricht A, Richards WA, Richards BD, Cosimano MP, Klinedinst MA. Psilocybin produces substantial and sustained decreases in depression and anxiety in patients with life-threatening cancer: A randomized double-blind trial. J Psychopharmacol. 2016 Dec;30(12):1181-1197. doi: 10.1177/0269881116675513.

Reference Type BACKGROUND
PMID: 27909165 (View on PubMed)

Ching THW, Amoroso L, Bohner C, D'Amico E, Eilbott J, Entezar T, Fitzpatrick M, Fram G, Grazioplene R, Hokanson J, Kichuk SA, Martins B, Patel P, Schaer H, Shnayder S, Witherow C, Pittenger C, Kelmendi B. Safety, feasibility, tolerability, and clinical effects of repeated psilocybin dosing combined with non-directive support in the treatment of obsessive-compulsive disorder: protocol for a randomized, waitlist-controlled trial with blinded ratings. Front Psychiatry. 2024 Jan 9;14:1278823. doi: 10.3389/fpsyt.2023.1278823. eCollection 2023.

Reference Type DERIVED
PMID: 38264632 (View on PubMed)

Other Identifiers

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2000032623

Identifier Type: -

Identifier Source: org_study_id

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