Feasibility, Clinical Effects, and Safety of Psilocybin-assisted Psychotherapy for Treatment-resistant OCD

Evaluating the Feasibility, Clinical Effects, and Safety of Psilocybin-assisted Psychotherapy for Treatment-resistant Obsessive-compulsive Disorder: An Open-label Clinical Trial

Feasibility, Clinical Effects, and Safety of Psilocybin-assisted Psychotherapy for Treatment-resistant OCD (NCT06299319) is a Phase 1 interventional studying Obsessive-Compulsive Disorder, sponsored by Centre for Addiction and Mental Health. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

Psilocybin, the chemical component of "magic mushrooms", has been administered with psychotherapy in several randomized clinical trials (RCTs) showing large and sustained antidepressant effects. There is interest to see if similar effects may be provided in those with obsessive compulsive disorder (OCD). The purpose of this study is to evaluate the safety, feasibility, and clinical effects of psilocybin administration in those with OCD. Ten participants with treatment-resistant OCD will receive two doses of 25mg of psilocybin under supportive conditions, two weeks apart. The investigators hypothesize that two sessions of psilocybin 25mg administered under supportive conditions to participants with treatment-resistant OCD will lead to significant reductions in OCD symptoms.

What Stage of Research Is This?

Phase 1 trials test a new treatment for the first time in humans, focusing on safety, dosing, and how the body processes the drug. For Obsessive-Compulsive Disorder, a Phase 1 study typically enrolls a small number of participants — often healthy volunteers or patients who have exhausted standard treatment options. Phase 1 results determine whether a treatment moves into larger Phase 2 efficacy studies.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

With a target enrollment of 10 participants, this is a small study — typical of early-phase research, rare-disease trials, or pilot studies designed to generate preliminary signal before a larger study is launched.

Who May Be Eligible (Plain English)

Who May Qualify: - Adults 18 to 65 years old; - Are outpatients - Must be deemed to have capacity to provide willing to sign a consent form; - Must sign and date the willing to sign a consent form form; - Stated willingness to comply with all study procedures; - Ability to read and communicate in English, such that their literacy and comprehension is sufficient for understanding the consent form and study questionnaires, as evaluated by study staff obtaining consent; - Primary The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnosis of obsessive compulsive disorder (OCD) based on medical records and assessment using the Structured Clinical Interview for DSM-5 (SCID-5) administered at the first screening visit; - Participants diagnosed with treatment-resistant OCD defined as individuals with a score of ≥ 16 on the YBOCS (i.e. moderate symptom severity) and that have not responded to two or more separate pharmacological interventions and one or more trials of cognitive behavioural therapy (CBT); there is no upper limit on the number of treatment failures; - Individuals with an estimated glomerular filtration rate (eGFR) above 40mL/min/1.73m2 and all blood work within normal limits as assessed by clinical laboratory tests at Screening (V1) - Ability to take oral medication; - Individuals who are capable of becoming pregnant: use of highly effective contraception for at least 1 month prior to screening and agreement to use such a method during study participation; - Individuals who are willing to and have tapered off current OCD medications for a minimum of 2-weeks prior to Baseline (V2) and whose physician confirms that it is safe for them to do so; ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

Inclusion Criteria: * Adults 18 to 65 years old; * Are outpatients * Must be deemed to have capacity to provide informed consent; * Must sign and date the informed consent form; * Stated willingness to comply with all study procedures; * Ability to read and communicate in English, such that their literacy and comprehension is sufficient for understanding the consent form and study questionnaires, as evaluated by study staff obtaining consent; * Primary The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) diagnosis of obsessive compulsive disorder (OCD) based on medical records and assessment using the Structured Clinical Interview for DSM-5 (SCID-5) administered at the first screening visit; * Participants diagnosed with treatment-resistant OCD defined as individuals with a score of ≥ 16 on the YBOCS (i.e. moderate symptom severity) and that have not responded to two or more separate pharmacological interventions and one or more trials of cognitive behavioural therapy (CBT); there is no upper limit on the number of treatment failures; * Individuals with an estimated glomerular filtration rate (eGFR) above 40mL/min/1.73m2 and all blood work within normal limits as assessed by clinical laboratory tests at Screening (V1) * Ability to take oral medication; * Individuals who are capable of becoming pregnant: use of highly effective contraception for at least 1 month prior to screening and agreement to use such a method during study participation; * Individuals who are willing to and have tapered off current OCD medications for a minimum of 2-weeks prior to Baseline (V2) and whose physician confirms that it is safe for them to do so; * Individuals who are willing to and have tapered off current inhibitors of 5'-diphospho-glucuronosyltransferase (UGT)1A9 and 1A10, aldehyde dehydrogenase inhibitors (ALDHs) and alcohol dehydrogenase inhibitors (ADHs) for a minimum of 2-weeks (or more depending on the medication) prior to Baseline (V2) and for the duration of the study and whose physician confirms that it is safe for them to do so; and * Agreement to adhere to Lifestyle Considerations (section 4.5) throughout study duration. Exclusion Criteria: * Pregnant as assessed by a urine pregnancy test at Screening (V1) and Baseline (V2) or individuals that intend to become pregnant during the study or are breastfeeding; * Treatment with another investigational drug or other intervention within 30 days of Screening (V1); * Have initiated psychotherapy in the preceding 12 weeks prior to Screening (V1); * Have a DSM-5 diagnosis of substance use disorder (use of tobacco and prescribed opioids are permitted) within the preceding 6 months; * Have active suicidal ideation as determined by the C-SSRS and/or clinical interview. Significant suicide risk is defined by suicidal ideation as endorsed by items 4 or 5 of the C-SSRS; * Any DSM-5 lifetime diagnosis of a schizophrenia-spectrum disorder; psychotic disorder (unless substance induced or due to a medical condition), bipolar I or II disorder, paranoid personality disorder, borderline personality disorder, or neurocognitive disorder as determined by medical history and the SCID-5 clinical interview; * Any first-degree relative with a diagnosis of schizophrenia-spectrum disorder; psychotic disorder (unless substance-induced or due to a medical condition); or bipolar I or II disorder as determined by the family medical history form and discussions with the participant; * Have contraindications to transcranial magnetic stimulation (TMS) as determined by the transcranial magnetic stimulation adult safety screen (TASS) questionnaire; * Have a history of seizures; * Are taking anticonvulsants or benzodiazepines (Lorazepam up to 2mg/day is acceptable); * Presence of a relative or absolute contraindication to psilocybin, including a drug allergy, recent stroke history, uncontrolled hypertension, low or labile blood pressure, recent myocardial infarction, cardiac arrhythmic, severe coronary artery disease, or moderate to severe renal or hepatic impairment; * Use of classic psychedelic drugs within the previous 12 months; OR * Any other clinically significant physical illness including chronic infectious diseases or any other major concurrent illness that, in the opinion of the investigator, may interfere with the interpretation of the study results or constitute a health risk for the participant if they take part in the study.

Treatments Being Tested

DRUG

Psilocybin

The psilocybin used in this study meets quality specifications suitable for human research use. The active drug is encapsulated using a hydroxypropyl methylcellulose (HPMC) capsule and contains 25 mg of psilocybin. The psilocybin will be administered twice during the trial, in conjunction with supportive therapy.

Locations (1)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

Centre for Addiction and Mental Health

Toronto, Ontario, Canada

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT06299319), the sponsor (Centre for Addiction and Mental Health), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT06299319 clinical trial studying?

Psilocybin, the chemical component of "magic mushrooms", has been administered with psychotherapy in several randomized clinical trials (RCTs) showing large and sustained antidepressant effects. There is interest to see if similar effects may be provided in those with obsessive compulsive disorder (OCD). The purpose of this study is to evaluate the safety, feasibility, and clinical effects of psilocybin administration in those with OCD. Ten participants with treatment-resistant OCD will receive two doses of 25mg of psilocybin under supportive conditions, two weeks apart. The investigators hyp… The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT06299319?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT06299319?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT06299319. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT06299319. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.