Effectiveness and safety of psychosocial interventions for the treatment of cannabis use disorder: A systematic review and meta-analysis.

Aim: To evaluate the effectiveness, safety and cost-effectiveness of psychosocial interventions for cannabis use disorder (CUD).

Methods: A systematic review of randomized controlled trials (RCTs; PROSPERO protocol CRD42024553382) of psychosocial interventions for CUD lasting >4 sessions, delivered synchronously, to individuals with CUD aged ≥16 years, in inpatient, outpatient or community-based settings. We searched databases (MEDLINE/PsycInfo/Cochrane CENTRAL) to 12 June 2024. We assessed results using Risk of Bias 2 and conducted pairwise meta-analyses. Primary outcomes were continuous- and point-abstinence and withdrawal intensity at the end of treatment, treatment completion and adverse events.

Results: We included 22 RCTs (3304 participants). Relative to an inactive/non-specific comparator, cognitive-behavioural therapy with motivation enhancement (MET-CBT) increased point abstinence [odds ratio (OR) = 18.27; 95% confidence interval (9.00-37.07)] and continuous abstinence [OR = 2.72; (1.20-6.19)], but reduced treatment completion [OR = 0.53; (0.35-0.85)]. Dialectical behavioural/acceptance and commitment therapy increased point abstinence versus inactive/non-specific comparator [OR = 4.34; (1.74-10.80)]. The effect of MET-CBT plus affect management versus MET-CBT on point abstinence was OR = 7.85 (0.38-163.52). The effect of MET-CBT plus abstinence-based contingency management versus MET-CBT on point abstinence was OR = 3.78 (0.83-17.25), and on continuous abstinence OR = 1.81 (0.61-5.41). For MET-CBT plus abstinence-contingency management versus MET-CBT plus attendance-contingency management, the effect on point abstinence was OR = 1.61 (0.72-3.60), and on continuous abstinence OR = 2.04 (0.75-5.58). The effect of community reinforcement on point abstinence was OR = 0.29 (0.04-1.90) versus MET-CBT, and on continuous abstinence OR = 47.36 (16.00-140.21) versus non-specific comparator. Interventions other than MET-CBT may not affect treatment completion. No adverse events were reported. No study reported withdrawal intensity. Two economic evaluations reported higher costs for more complex interventions and contingency management.

Conclusions: Cognitive-behavioural therapy with motivation enhancement and dialectical behavioural/acceptance and commitment therapy may increase abstinence among people with cannabis use disorder relative to an inactive/non-specific comparator. The conclusions remain tentative due to low- to very low-certainty evidence and the small number of studies.