Effects of stopping cannabis use on depression and cognition
Official title: Effects of Extended Cannabis Abstinence on Clinical and Cognitive Outcomes in Patients With Co-Morbid Major Depressive and Cannabis Use Disorders
Run by Centre for Addiction and Mental Health · NCT04935619 · Data updated 2026-11-12
This study is testing if stopping cannabis use for 28 days can help people with depression and cannabis addiction feel better and think more clearly.
Quick facts
| Study type | Interventional |
|---|---|
| Ages | 18 Years to 55 Years |
| Sex | All |
| Enrollment | 52 (estimated) |
| Sponsor | Centre for Addiction and Mental Health Academic / other |
| Locations | 1 site (Toronto, Ontario) |
| Status | Recruiting |
| Started | July 21, 2021 |
| Main results expected | June 30, 2027 |
| Study ends | August 31, 2027 |
| Registry record updated | February 24, 2025 |
| Trial ID | NCT04935619 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Ideal candidates are adults aged 18-55 with moderate to severe cannabis use disorder and major depressive disorder who are stable on antidepressant medication.
✕Probably not a fit
Patients with recent substance use disorders involving alcohol or other illicit drugs, or those with current suicidal ideation, may not benefit from this study.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This study investigates the impact of a 28-day cannabis abstinence period on patients with major depressive disorder (MDD) who also have cannabis use disorder (CUD). Using a randomized controlled design, participants will be assigned to either a contingent reinforcement group or a non-contingent reinforcement group to assess changes in depressive symptoms and cognitive function. The study aims to clarify causal relationships between cannabis use and depression, which have been unclear in previous research. By focusing on a specific patient population, the study seeks to provide insights into effective treatment strategies for those suffering from both MDD and CUD.
Why it matters
Potential benefit: If successful, this study could lead to improved treatment outcomes for patients with co-occurring cannabis use disorder and major depressive disorder.
How similar studies have gone: Previous studies have shown promising results regarding cannabis abstinence improving depressive symptoms and cognition, suggesting potential success for this approach.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * All participants must be between the ages 18-55 * Meet SCID for DSM-5 diagnostic criteria for cannabis use disorder, moderate to severe * Meet SCID for DSM-5 diagnostic criteria for Major Depressive Disorder * Be an outpatient receiving a stable dose of antidepressant medication for at least three months (to ensure stability of depressive symptoms * Have a Hamilton Depression Rating Scale (HDRS-17) at baseline assessment in the range of 12-25.. * Have a Full-Scale IQ ≥ 80 as determined by the WTAR * Be a non-treatment seeking cannabis user * Evidence of sufficient motivation and effort as measured by a Test of Memory Malingering (TOMM) score ≥ 45. Exclusion Criteria: * Meets criteria for substance use disorder of alcohol or other illicit substances within the past 6 months (with the exception of cannabis, nicotine, or caffeine) * Positive urine screen for illicit substances other than cannabis, nicotine, or caffeine * Current suicidal or homicidal ideation * Psychotic disorder diagnosis (e.g. schizoaffective disorder, major depression with psychotic features) as determined by the SCID * Treatment seeking for cannabis use * Meet SCID for DSM-5 diagnostic criteria for Bipolar Disorder * Head Injury\> 5 minutes LOC * Exceed upper and lower cut-offs on HSRD-17 (See Inclusion Criteria)
Where it's running
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Centre for Addiction and Mental Health
Toronto, Ontario, Canada Recruiting
Study contacts
- Principal investigator: Tony P George, MD., FRCPC — Camh
- Study coordinator: Maryam Sorkhou, HBSc
- Email: maryam.sorkhou@mail.utoronto.ca
- Phone: 4165358501
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.