Effects of legal access versus illegal market cannabis on use and mental health: A randomized controlled trial
Abstract
Abstract Aims We measured the effects of public health‐oriented cannabis access compared with the illegal market on cannabis use and related mental health outcomes in adult cannabis users. Design This was a two‐arm, parallel group, open‐label, randomized controlled trial. Follow‐up outcome measurement took place after 6 months. Setting The study was conducted in Basel‐Stadt, Switzerland. Participants A total of 378 adult (aged ≥18 years) cannabis users were enrolled and randomized between August 2022 and March 2023, although only 374 users who completed baseline measures could be included. Intervention and Comparator Participants were randomly assigned to the intervention group with public health‐oriented recreational cannabis access in pharmacies (regulated cannabis products, safer use information, voluntary counseling, no advertisement; 189/188) or the illegal market control group (continued illicit cannabis sourcing; 189/186). Measurements The primary outcome was self‐reported severity of cannabis misuse after 6 months, as measured by the Cannabis Use Disorders Identification Test – Revised (range 0–32). Secondary outcomes involved depressive, anxiety, and psychotic symptoms, cannabis consumption amount, alcohol, and drug use. Findings Ten participants were not followed (2.7%). Primary analysis included those with complete data (182 vs. 182). There was some evidence of a difference in cannabis misuse between the legal cannabis intervention group (mean [M] = 10.1) and the…
How strong is the evidence?
Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 374 participants or records.
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