NCT04935619

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

Effects of Extended Cannabis Abstinence on Clinical and Cognitive Outcomes in Patients With Co-Morbid Major Depressive and Cannabis Use Disorders

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 52 (estimated)
• Sponsor: Centre for Addiction and Mental Health · Academic / Other
• Sex: All
• Age: 18 Years – 55 Years
• Healthy volunteers: Not accepted

Summary

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.

Detailed description

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. To date, most studies of cannabis use in MDD were cross-sectional in design, and therefore causal relationships are unclear. The investigators previous studies in cannabis dependent patients with schizophrenia suggest that extended cannabis abstinence (up to 28 days) using contingent reinforcement is associated with improvements in specific areas of cognition (e.g. verbal learning and memory) and depressive symptoms. A more recent study using an open-label design demonstrated that 28 days of cannabis abstinence improves depressive symptoms and anhedonia in participants (N=11) with co-occurring MDD and CUD. The investigators propose a controlled cannabis abstinence paradigm in patients with co-morbid MDD and CUD (N=52) to further investigate these findings. Stabilized MDD patients with moderate to severe CUD will be randomly assigned to one of two groups: 1) A contingent reinforcement (CR) intervention (n=26); 2) a non-contingent reinforcement (NCR) intervention (n=26), which will serve as a time and non-abstinence control. In the CR group, subjects achieving biochemically-verified cannabis abstinence at study endpoint (Day 28) will receive a $300 contingent payment; participants in the NCR group will not receive this contingent payment. The primary outcomes are: 1) cannabis abstinence rates at Day 28 in CR versus NCR groups; 2) changes in mood (depressive), anxiety and sleep symptoms over the 28-day assessment period. Secondary outcomes include cognition.

Conditions

• Cannabis Use
• Major Depressive Disorder
• Cognitive Impairment

Interventions

Type	Name	Description
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.

Timeline

• Start date: 2021-07-21
• Primary completion: 2027-06-30
• Completion: 2027-08-31
• First posted: 2021-06-23
• Last updated: 2025-02-24

Locations

1 site across 1 country: Canada