Effectiveness of cognitive behavioral therapy for harmful cannabis use: a systematic review and meta-analysis

This systematic review and meta-analysis evaluated the effectiveness of cognitive behavioral therapy (CBT) for cannabis use. Randomized controlled trials (RCTs) assessing CBT for cannabis use were systematically searched in MEDLINE, PsycINFO, CINAHL, AMED, Cochrane Library, and clinical trial registries. Quality of the studies were appraised using the Cochrane Risk of Bias tool (RoB1). A total of 2347 records were screened, of which nine RCTs involving 1280 participants were eligible for inclusion. Meta-analysis results showed that CBT didn't produce significant reductions in cannabis use frequency, compared with contingency management, treatment as usual and other psychosocial interventions. The pooled estimates were 0.12 (95% Confidence Interval [CI]: -0.02, 0.26; p=0.10) in short-term, -0.03 (95% CI: -0.18, 0.13; p=0.75) medium-term, and 0.01 (95% CI: -0.18, 0.20; p=0.91) long-term follow-ups. Daily cannabis consumption outcomes were inconsistent, showing a significant medium-term effect (-0.50; 95% CI: -0.90, -0.10; p<0.05) but insignificant effects at other time points. Limitations included study heterogeneity, small sample sizes, and risk of bias. Findings highlight the need for standardized CBT content, integrated with adjunctive therapies, to enhance treatment outcomes for individuals with cannabis use.