Actively Recruiting
Feasibility, Clinical Effects, and Safety of Psilocybin-assisted Psychotherapy for Treatment-resistant OCD
Led by Centre for Addiction and Mental Health · Updated on 2026-03-27
10
Participants Needed
1
Research Sites
99 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
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.
CONDITIONS
Official Title
Feasibility, Clinical Effects, and Safety of Psilocybin-assisted Psychotherapy for Treatment-resistant OCD
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Adults 18 to 65 years old
- Outpatients
- Must have capacity to provide informed consent
- Must sign and date the informed consent form
- Willingness to comply with all study procedures
- Ability to read and communicate in English sufficiently for consent and questionnaires
- Diagnosed with obsessive-compulsive disorder (OCD) by DSM-5 criteria confirmed via clinical interview
- Treatment-resistant OCD defined by a Yale-Brown Obsessive Compulsive Scale (YBOCS) score of 16 or higher
- Failure to respond to two or more pharmacological treatments and at least one trial of cognitive behavioral therapy
- Estimated glomerular filtration rate (eGFR) above 40 mL/min/1.73m2 and normal blood tests at screening
- Ability to take oral medication
- If capable of becoming pregnant, use of highly effective contraception for at least 1 month prior to screening and agreement to continue during study
- Willingness and ability to taper off current OCD medications for at least 2 weeks prior to baseline with physician approval
- Willingness and ability to taper off certain enzyme inhibitors and alcohol dehydrogenase inhibitors for at least 2 weeks prior to baseline and during study with physician approval
- Agreement to adhere to lifestyle considerations throughout the study
You will not qualify if you...
- Pregnant, breastfeeding, or intending to become pregnant during the study
- Treatment with another investigational drug or intervention within 30 days prior to screening
- Started psychotherapy within 12 weeks prior to screening
- Diagnosis of substance use disorder within the last 6 months (excluding tobacco and prescribed opioids)
- Active suicidal thoughts or significant suicide risk as determined by clinical assessment
- Lifetime diagnosis of schizophrenia-spectrum disorder, psychotic disorder (unless substance-induced), bipolar I or II disorder, paranoid personality disorder, borderline personality disorder, or neurocognitive disorder
- First-degree relative with schizophrenia-spectrum disorder, psychotic disorder, or bipolar I or II disorder
- Contraindications to transcranial magnetic stimulation as per safety screening
- History of seizures
- Current use of anticonvulsants or benzodiazepines (except lorazepam up to 2mg/day)
- Allergies or medical conditions contraindicating psilocybin including recent stroke, uncontrolled hypertension, heart conditions, or moderate to severe kidney or liver impairment
- Use of classic psychedelic drugs within the previous 12 months
- Any other significant physical illness that may affect study results or pose health risks as judged by the investigator
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Trial Site Locations
Total: 1 location
1
Centre for Addiction and Mental Health
Toronto, Ontario, Canada, M6J 1H1
Actively Recruiting
Research Team
G
Gwyneth Zai, MD, MSc, PhD
CONTACT
E
Ezmond Cheung, BPsySci
CONTACT
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NA
Model
SINGLE_GROUP
Primary Purpose
TREATMENT
Number of Arms
1
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