Effectiveness and clinical predictors of a virtual based combined cognitive behavioral and motivational enhancement group therapy for adults with cannabis use disorder

BACKGROUND: Cannabis use has increased in recent years, while perceptions of harm have declined. Cognitive behavioural therapy (CBT), motivational enhancement therapy (MET), and their combinations (CBT-MET) are evidence-based interventions for CUD, though their effectiveness when delivered virtually is underexplored. This study evaluated the clinical efficacy of a virtual 12-week group-based CBT-MET program in individuals with CUD and examined baseline predictors of treatment response. METHODS: A retrospective analysis was conducted on 116 adults enrolled in a virtual group-based CBT-MET program between 2020 and 2023. Participants completed weekly self-report assessments of cannabis use and biweekly assessments of depression (PHQ-9) and anxiety (GAD-7). Cannabis craving (MCQ) and a measure of problematic cannabis use (CUDIT) were assessed at baseline and post-treatment. Wilcoxon signed-rank tests evaluated changes among completers (≥ 75 % attendance), and linear mixed models identified baseline predictors of change over time. RESULTS: Of the 116 participants, 79 (68 %) completed the program, indicating high retention. Among completers, significant reductions were observed in cannabis use frequency (p < 0.01), quantity (p < 0.01), craving (p < 0.01), depression (p < 0.01), and anxiety (p = 0.02). Higher baseline cannabis use predicted greater reductions in cannabis frequency and quantity, while higher self-efficacy predicted lower cannabis use frequency across treatment. Individuals with co-occurring substance use disorders other than tobacco demonstrated smaller reductions in cannabis quantity. CONCLUSION: Virtual CBT-MET was feasible and led to significant reductions in cannabis use and psychiatric symptoms among individuals with CUD. Baseline cannabis use patterns and self-efficacy were key predictors of reduction in cannabis use, highlighting the need for personalized approaches in future interventions.