Cannabis use prevalence before and early after partial legalisation in Germany

Background and AimsOn April 1st, 2024, Germany implemented the Act on the Handling of Cannabis for Non-Medical Use (KCanG), allowing adults to cultivate and possess recreational cannabis. We assessed whether this policy shift was associated with a change in the prevalence of cannabis use in the general population and in daily or almost daily cannabis use. DesignA series of 21 repeated cross-sectional surveys conducted between April/May 2022 and October/November 2025 (covering the period approximately two years before and one and a half years after the KCanG). SettingPopulation of Germany. ParticipantsA total of 32,991 people aged 14-64 years, including 2,092 (6.3%) people who used cannabis in the past 12 months. MeasurementsPast 12-month cannabis use (at least once). In past 12-month users: daily or almost daily use. To test a potential change in prevalence following the KCanG, we used piecewise binomial logistic regression models using the exact date of each wave as the predictor variable, allowing for a change in the slope at the first full wave after implementation of the KCanG in April 2024, with a random effect for wave. We conducted this analysis for the total sample as well as stratified by gender (male vs. female), age (14-24 vs. 25-64 years), and for daily or almost daily cannabis use in the subgroup of people who used cannabis in the past 12 months. Sensitivity analyses used alternate intervention dates (in-time placebo tests). FindingsThe prevalence of cannabis use and the share of (almost) daily users among 12-month users remained largely stable before and after the law reform. None of the slope coefficients before the introduction of the KCanG were statistically significant (all p [≥] .08), and none of the coefficients for the change in the slope were statistically significant (all p [≥] .31). Results of sensitivity analyses confirmed the stable trends for both outcomes. ConclusionsThe legislation of cannabis introduced in Germany in April 2024 was not associated with a change in trends of 12-month cannabis use prevalence early (1.5 years) after implementation, and also not with a change in the proportion of heavy users among past-12-month users. We recommend continued close monitoring of trends using multiple data sources and over a longer post-implementation period, as the effects of the legislation may not have fully unfolded yet.