Cannabis Use Disorder Was the Strongest Predictor of Relapse in Patients With Dual Diagnoses

Patients with co-occurring disorders (COD) had a 39.8% relapse rate vs 26.4% for those without. Among COD patients, cannabis use disorder had a 53.3% relapse rate and was the strongest predictor (OR=2.31, 95% CI: 1.34-4.00). Protective factors included older age, being female (OR=0.56), and higher intrinsic motivation (OR=0.58).

Prospective cohort study of 611 SUD inpatients (289 with COD, 322 without). Demographics, motivation, mental distress, and diagnoses assessed at baseline. Relapse assessed at 3 months post-treatment (70% retention rate). Multivariate logistic regression identified predictors.

Cannabis use disorder is often perceived as less severe than other substance use disorders, but this study found it was the single strongest predictor of relapse among patients with dual diagnoses. This suggests cannabis-specific treatment components may be needed in dual-diagnosis programs.

Dual-diagnosis treatment programs may need to pay special attention to cannabis use disorder. The high relapse rate for CUD, combined with its association with psychiatric symptoms, suggests that addressing cannabis use should be a priority in these settings.

Three-month follow-up may be too short to capture longer-term outcomes. 30% loss to follow-up may introduce bias. Single-country setting (Norway) limits generalizability. Self-reported relapse may underestimate actual use.