PsilOCD: A Pharmacological-Challenge Feasibility Study

Imperial College London19 enrolled

Overview

The purpose of this study is to assess the impact of psilocybin on cognitive inflexibility and neural plasticity in a cohort of people with obsessive-compulsive disorder (OCD).

This mechanistic study will utilise a within-subjects design, administering up to 10mg of psilocybin to participants with OCD (DSM-5 criteria) on two separate instances spaced four weeks apart. To ensure consistency and participant safety, dosing will occur under medical supervision with psychological support from two experienced therapists. Before and after each session, participants will engage in virtual preparation and integration sessions led by their therapists. Cognitive tasks will be administered in the days following each dosing session. Additionally, acute post-dosing EEG recordings will be conducted, and blood samples will be taken after each dosing session. OCD symptoms will also be assessed seven times throughout the trial by an external blinded psychiatrist, serving as a secondary outcome. Collectively, these measures aim to evaluate changes in cognitive inflexibility, decision-making abilities, neuroplasticity (peripheral blood markers and EEG measures), inflammation (peripheral blood markers), and symptomatology following each dosing session.

Study Type

INTERVENTIONAL

Allocation

Purpose

OTHER

Masking

NONE

Enrollment

Conditions

Obsessive-Compulsive Disorder

Interventions

Psilocybin (COMP360)DRUG

Up to 10mg on two occasions

Eligibility

Sex: ALLMin age: 20 YearsMax age: 65 Years

Medical Language ↔ Plain English

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. 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).

Locations (1)

CIPPRes Clinic

London, United Kingdom

Outcomes

Primary Outcomes

Intradimensional-extradimensional (ID-ED) set shift

Scores on this neurocognitive task administered as part of the Cambridge Neuropsychological Test Automated Battery (CANTAB). ID-ED performance is an established measure of cognitive inflexibility in OCD (Chamberlain et al., Am J Psychiatry, 2007), with worse scores corresponding to decreased flexibility.

Time frame: 4 weeks

The visual long-term potentiation (vLTP) electroencephalogram (EEG) paradigm (acute quantified changes in neuroplasticity in the visual system).

We will assess acute changes in homosynaptic neuroplasticity using the visual long-term potentiation (vLYTP) EEG paradigm. In this paradigm, we induce neural plasticity in the occipital cortex by exposing participants to visual stimuli of varying frequencies. This task specifically quantifies homosynaptic plasticity because it triggers changes in neighbouring neurons within the occipital cortex.

Time frame: 8 weeks

Secondary Outcomes

Clinical measures of compulsivity of relevance to OCD including Yale-Brown Obsessive Compulsive Scale (Y-BOCS)

Assess OCD symptoms over the study's duration (with higher scores corresponding to worse symptoms in all scales mentioned)

Time frame: 8 weeks

Cognitive measure: Reversal learning task (administered as part of the Cambridge Neuropsychological Test Automated Battery (CANTAB))

Assesses ability to adapt to changing contingencies; higher scores indicate better cognitive flexibility

Time frame: 4 weeks

Cognitive measure: Information-seeking task

It tests participants' confidence and ability to make decisions involving uncertainty by monitoring their tendency to seek extra information (recently developed by Lion Schulz and colleagues, 2020)

Time frame: 4 weeks

Data from ClinicalTrials.gov

This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.