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Extended Effects of Cannabis Abstinence on Clinical Symptoms and Cognition in Depression

The prevalence of major depressive disorder (MDD) is \~5.0%, and rates of co-occurring SUDs in these patients approach 40-50%. Specifically, rates of co-morbid cannabis use disorder (CUD) in patients with MDD are elevated 2-3 fold compared to 2.9% in the general population, and is associated with poorer treatment outcomes and impaired cognitive and psychosocial functioning in comparison to MDD patients without CUD. Most studies of cannabis use in MDD are cross-sectional in design, and therefore causal…

ClinicalTrials.gov IDNCT04935619

PhaseNA

Enrollment52

SponsorCentre for Addiction and Mental Health

Age18 Years

SexALL

I'm interested View official listing

Conditions studied

Cannabis Use, Major Depressive Disorder, Cognitive Impairment

About this study

Interventions

Behavioral: Contingency Reinforcement — Subjects will be randomly assigned on a 1:1 ratio to either the Contingency Reinforcement or Non-Contingency Reinforcement Intervention prior to their in-person screening visit.
Behavioral: Non-Contingency Reinforcement — Subjects will be randomly assigned on a 1:1 ratio to either the Contingency Reinforcement or Non-Contingency Reinforcement Intervention prior to their in-person screening visit.

Primary outcomes

Changes in Depressive Symptomology from Baseline to Week 4 ([Time Frame: Weekly (Day 0, Day 7, Day 14, Day 21, Day 28)])
Changes in Anxious Symptomology from Baseline to Week 4 ([Time Frame: Weekly (Day 0, Day 7, Day 14, Day 21, Day 28)])
Changes in Sleep Symptomology from Baseline to Week 4 ([Time Frame: Weekly (Day 0, Day 7, Day 14, Day 21, Day 28)])
Changes in Anhedonia from Baseline to Week 4 ([Time Frame: Weekly (Day 0, Day 7, Day 14, Day 21, Day 28)])

Eligibility information

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)

Study locations

Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8 Canada

Before you participate: Varda Clinical is an independent discovery tool, not the study sponsor or a medical provider. Eligibility can only be determined by the official study team. Discuss potential risks and benefits with a qualified healthcare professional.

Source: ClinicalTrials.gov. Record last refreshed by Varda Clinical: 2026-09-27.