Recreational cannabis access via pharmacies: A 1-year Swiss study on cannabis use and mental health.

BACKGROUND: While cannabis use has been linked to poorer mental health, the effects of regulated access remain unexplored. This study examined changes in psychopathology and cannabis-use patterns under pharmacy-based regulated access (pharmacist-dispensed, max 20% THC, ≤10g THC/month) in Switzerland over 1 year. METHODS: Linear mixed-effects models analyzed changes in depressive and anxiety symptoms, problematic cannabis use, and cannabis-use frequency and quantity among 374 regular cannabis users with pharmacy access (mean age 35.8; 81% male), from baseline to 1-year follow-up, with subgroups by baseline problematic use (CUDIT-R ≥ 13 vs < 13). RESULTS: Mean depressive symptoms (p < .0001), anxiety (p = .0008), and problematic cannabis use (CUDIT-R; p = .0002) decreased significantly but by small amounts (PHQ-9 5.37 to 4.53). The proportion exceeding clinical thresholds did not change significantly over time (CUD: 32.7% to 28.6%, p = .126). Cannabis-use frequency increased modestly (p = .0042) and quantity was unchanged. Time explained almost none of the variance (marginal R² < .01); most of the variance reflected stable between-person differences (conditional R² =.57-.70). A group-by-time interaction showed a larger CUDIT-R reduction in the high-risk group (p < .0001). Adjusting for medication left all effects unchanged. CONCLUSION: Over one year of pharmacy-based regulated access, psychopathological symptoms and problematic cannabis use showed small but significant mean decreases, while the proportion above clinical thresholds remained unchanged. Although the uncontrolled design precludes causal claims, these findings suggest that regulated access was not associated with deterioration in mental health or cannabis use.