Effects of legal access versus illegal market cannabis on use and mental health: A randomized controlled trial.
Baltes-Flueckiger et al.·Addiction (Abingdon, England)Impact 3.3
MixedGRADEModerate4 citations
Samplen = 374 Pat.
Duration6 months
ControlContinued procurement via the illegal market
EndpointCUDIT-R
Blindingoffen
DesignRCT
Cannabinoidvollspektrum
”Key finding
Weak evidence for reduction of cannabis abuse in the legal group (10,1 vs. 10,9; p=0,052), but no statistically significant effects on secondary outcomes (depression, anxiety, psychotic symptoms).
Summary
n=374 adult cannabis users (Switzerland), randomised to legalised pharmacy access vs. illegal market (6-month follow-up); intervention group showed a tendency toward lower CUDIT-R score (M=10.1 vs. 10.9, β=-0.69, 95% CI [-1.4 to 0.0], p=0.052); subgroup analysis: significant reduction only in users with polysubstance use (p<0.001); no significant differences in depression, anxiety, psychotic symptoms, or amount of use.
InterventionRegulated cannabis access via pharmacies with public health measures (regulated products, safer-use information, voluntary counselling, no marketing)
C
ControlContinued procurement via the illegal market (control group)
O
OutcomeCannabis abuse (CUDIT-R) after 6 months: intervention group M=10,1 vs. control group M=10,9 (β=−0,69, 95% CI −1,4 to 0,0, p=0,052); subgroup analysis shows significant reduction only in cases of concurrent other drug use (p-interaction <0,001); no significant differences for secondary outcomes.
Confidence in the evidence
Very lowLowModerateHigh
Moderate
The third of four GRADE levels, the effect estimate is probably reliable.
Downgraded for
Risk of bias
Quality profile
Sample size★★★★★
BlindingOpen-label
Effect sizeMixed
Citations / year★★★★★
Authors
Baltes-Flueckiger L, Steinauer R, Meyer M, Guessoum A, Herrmann O, Mosandl CF, Kronschnabel J, Pichler EM, Vogel M, Walter M
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 illegal market control group (M = 10.9; beta = -0.69, 95% confidence interval [CI] = -1.4 to 0.0, P = 0.052). These results were supported by an intention-to-treat multiple imputation analysis (n = 374). Additional sub-group analysis by whether the participant used other drugs or not suggested that any reduction in cannabis misuse was confined to those in the legal cannabis intervention group who used other drugs (P(Interaction) < 0.001). We found no statistically significant changes in any of the secondary outcomes.
Conclusions: Public health-oriented recreational cannabis access may decrease cannabis use and cannabis-related harms, especially among those using other drugs.