Investigating cognitive function in psychosis patients and cannabis users

Investigating the Neural Correlates of Cognitive Function Associated With Cannabis Abstinence in Psychosis Patients and Non-Psychiatric Controls With Cannabis Use

Not applicable Interventional Douglas Mental Health University Institute · NCT05445180

This study is testing how taking a break from cannabis for 28 days affects thinking skills and brain activity in people with psychosis and those who use cannabis but don’t have mental health issues.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment134 (estimated)
Ages16 Years to 80 Years
SexAll
SponsorDouglas Mental Health University Institute Academic / other
Locations1 site (Montreal, Quebec)
Trial IDNCT05445180 on ClinicalTrials.gov

What this trial studies

This study examines the neurobiological basis of cognitive changes associated with 28 days of cannabis abstinence in individuals with psychosis and non-psychiatric controls who use cannabis. Participants will be randomized into either a cannabis abstinent group or a non-abstinent control group and will undergo magnetic resonance imaging (MRI) at the beginning and after 28 days. The study aims to explore brain activity, morphology, and the correlation between cognitive recovery and brain changes following abstinence. This research could provide insights into the cognitive impairments linked to cannabis use and inform future interventions.

Who should consider this trial

Good fit: Ideal candidates include individuals with a diagnosis of psychotic disorders who are heavy cannabis users and can provide informed consent.

Not a fit: Patients with current substance use disorders other than cannabis or those with contraindications for MRI may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved understanding and treatment options for cognitive dysfunction in patients with psychosis who use cannabis.

How similar studies have performed: While the specific approach of this study may be novel, previous research has indicated that cannabis abstinence can lead to cognitive improvements in users, suggesting potential for success.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Able to provide informed consent in English or French
* Heavy cannabis use (defined as weekly cannabis use for at six months) and/or DSM-5 diagnosis of CUD
* Have a Full-Scale IQ ≥ 75
* Meet DSM-5 criteria for a psychotic disorder (psychosis patient arm only)
* Be an outpatient receiving a stable dose of medication(s) for at least two months (psychosis patient arm only)
* Clinically stable (as measured by the PANSS-6, total score \<30) (psychosis patient arm only)

Exclusion Criteria:

* current SUD (other than CUD)
* MRI contraindications
* Positive urine screen for psychoactive substances other than cannabis, nicotine, or caffeine
* Current suicidal or homicidal ideation
* Head injury requiring hospitalization or loss of consciousness \> 5 minutes
* Current medical diseases that requires hospitalization or regular monitoring
* Being pregnant
* DSM-5 Axis 1 diagnosis (other than CUD) (non-psychiatric controls only)
* Taking psychotropic medication

Where this trial is running

Montreal, Quebec

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Psychotic DisordersCannabis Use DisorderCannabis DependenceCannabis UseSchizophreniaPsychosisCognitive DysfunctionMemory Impairment
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.