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

Cognitive Impairment | Major Depressive Disorder | Cannabis Use

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 relationships are unclear. This study investigates the effects of cannabis abstinence over a 28-day period in patients with MDD with co-occurring CUD using a randomized controlled design, namely contingent reinforcement.

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Participation Requirements

  • Sex:

    ALL

  • Eligible Ages:

    18 to 55

Participation 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)

Study Location

Centre for Addiction and Mental Health
Centre for Addiction and Mental Health
Toronto, Ontario
Canada

Contact Study Team

Study Sponsored By
Centre for Addiction and Mental Health
Participants Required
More Information
Study ID: NCT04935619