Clinical TrialObsessive-Compulsive Disorder (OCD)PsilocybinCompleted

PsilOCD: A Pharmacological-Challenge Feasibility Study

Single-group mechanistic feasibility study (n=19) administering up to 10 mg psilocybin (COMP360) on two occasions to people with OCD to assess cognitive inflexibility, neuroplasticity, and symptom changes.

Target Enrollment
19 participants
Study Type
Phase I interventional
Design
Non-randomized

Detailed Description

This within-subjects study administers up to 10 mg psilocybin on two dosing days separated by four weeks to participants meeting DSM-5 criteria for OCD; dosing is supervised medically with psychological support from two therapists.

Participants receive virtual preparation and integration sessions before and after each dosing day; cognitive tasks, acute EEG, and blood sampling assess neuroplasticity and inflammatory markers, with symptom ratings (Y-BOCS, MADRS) performed by a blinded external psychiatrist.

Outcomes focus on changes in cognitive flexibility, decision-making, peripheral neuroplasticity and inflammation markers, EEG measures, and OCD symptom trajectory across the dosing schedule.

Study Protocol

Preparation

2 sessions

Dosing

2 sessions

Integration

2 sessions

Therapeutic Protocol

support

Study Arms & Interventions

Psilocybin (COMP360)

experimental

All participants receive up to 10 mg psilocybin on two dosing days (4 weeks apart).

Interventions

  • Psilocybin10 mg
    via Oral• two sessions• 2 doses total

    COMP360; up to 10 mg administered on each of two dosing days (separated by 4 weeks)

Participants

Ages
20 – 65
Sexes
Male & Female

Inclusion Criteria

  • Key Inclusion Criteria:
  • Aged 20 to 65 years;
  • Any gender;
  • A primary diagnosis of OCD (based on the Mini-International Neuropsychiatric Interview (M.I.N.I.));
  • Has met diagnostic criteria for OCD for at least 12 months;
  • Willing to comply with protocol and associated lifestyle restrictions;
  • Adequate understanding of the English language to give informed consent and participate in the study;
  • Participant can attend visits as an outpatient;
  • Comfortable using a computer, access to internet from home, and willing to participate in some of the study visits via video-link.

Exclusion Criteria

  • Key Exclusion Criteria:
  • Current or past history of dependent (according to ICD10 criteria) substance use (not including nicotine and/or caffeine), Tourette's syndrome, autism spectrum disorder, epilepsy, organic mental disorder, or a personality disorder apart from obsessive-compulsive personality disorder;
  • Current or past history of psychosis or mania in themselves or a first-degree relative;
  • Unstable physical health;
  • Significantly abnormal clinical test result;
  • Heavy smoker, or unable to attend the dosing days (including the subsequent recovery part) without a smoking break;
  • Unwillingness to allow their GP or mental health practitioners to be informed of their participation (or, to allow study team access to Summary Care Record).

Study Details

Study Team

Sponsors & Collaborators

Locations

CIPPRes Clinic — London, United Kingdom

Related Publications

Single-dose (10 mg) psilocybin reduces symptoms in adults with obsessive-compulsive disorder: A pharmacological challenge study

Published
Authors
Pellegrini, L., Fineberg, N. A., O'Connor, S., Pereira De Souza, A. M. F. L., Godfrey, K., Reed, S., Peill, J. M., Healy, C. J., Rohani-Shukla, C., Lee, H., Carhart-Harris, R. L., Robbins, T. W., Nutt, D. J., Erritzoe, D.

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