What topics does this cannabis study cover?

This study covers research on: Addiction.

Where was this research published?

Published in The International journal on drug policy on September 11, 2026.

Germany’s cannabis reform showed no early change in use prevalence

Q: What did this research study find?

Across **23 repeated surveys** of **35,957 people aged 14–64**, past-year *cannabis use* remained **largely stable** before and after Germany’s 2024 reform.

Cannabis use prevalence before and early after partial legalisation in Germany.

The International journal on drug policy • September 11, 2026 • Highly Relevant

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AI Summary

This observational repeated-survey study examined whether Germany’s April 2024 Cannabis Act was associated with changes in cannabis use among people aged 14–64 years. Researchers analyzed 23 surveys conducted from April/May 2022 through March/April 2026, covering roughly two years before and two years after the reform. Among 35,957 respondents, 2,302 (6.4%) reported cannabis use in the previous 12 months. The main outcomes were any past-year use and daily or almost daily use.

The prevalence of past-year cannabis use and the share of heavy users remained largely stable before and after the law took effect. Statistical tests found no significant change in the trend after legalization, including across the examined gender and age groups. One pre-reform trend among daily or almost daily users was statistically significant, but the study found no significant change in trend attributable to the reform. Because this is an observational study of early population-level trends, the abstract cannot establish that the law caused—or will never cause—changes in cannabis use. The authors recommend continued monitoring over longer periods and across multiple data sources. This is an abstract-based summary; the full paper was not reviewed.

💡 Key Findings

Across 23 repeated surveys of 35,957 people aged 14–64, past-year cannabis use remained largely stable before and after Germany’s 2024 reform.

High

85%

The reform was not associated with a statistically significant change in the trend for past-year use or daily or almost daily use, including in the reported age and gender subgroup analyses.

High

85%

Among past-year users, a negative pre-reform trend in daily or almost daily use was statistically significant, but there was no significant change in that trend after the reform.

High

80%

The early findings cannot establish long-term effects of the law; the authors recommend monitoring over longer periods and using multiple data sources.

High

90%

📄 Original Abstract

BACKGROUND: On April 1st, 2024, Germany implemented the Cannabis Act (CanG), allowing adults to cultivate and possess recreational cannabis. We assessed whether this was associated with a change in the prevalence of cannabis use. METHODS: A series of 23 repeated surveys between April/May 2022 and March/April 2026 (covering the period approximately two years before and two years after the CanG). We measured past 12-month cannabis use (at least once; daily or almost daily use). Piecewise binomial logistic regression models used wave dates as predictors, allowing a slope change at the first full wave after April 2024, with a random effect for wave. Analyses covered the total sample and subgroups by gender, age (14-24 vs. 25-64 years), and daily or almost daily use among past 12-month users. Sensitivity analyses used alternate intervention dates (in-time placebo tests). RESULTS: Among 35,957 respondents aged 14-64 years, 2302 (6.4%) reported past 12-month cannabis use. The prevalence of cannabis use and proportion of daily or almost daily (heavy) users remained largely stable before and after the law reform. None of the slope coefficients before the introduction of the CanG were statistically significant (all p ≥ 0.07), except for the negative slope in daily or almost daily users in the subgroup of past 12-month users (-0.091, p = 0.04). Also, none of the coefficients for the change in the slope were statistically significant (all p ≥ 0.15). Sensitivity analyses supported these findings. CONCLUSIONS: Germany's 2024 cannabis reform was not associated with changes in 12-month use prevalence or heavy use early (two years) after implementation. Continued monitoring over longer periods and across multiple data sources is recommended, as effects may emerge later.

Paper Type

📄 Research

Publication

Journal: The International journal on drug policy
Published: September 11, 2026
PMID: 42727136
DOI: 10.1016/j.drugpo.2026.105501

Authors (5)

Daniel Kotz Institute of General Practice, Addiction Research and Clinical Epidemiology Unit, Medical Faculty of the Heinrich-Heine-University Düsseldorf, Germany; Department of Behavioural Science and Health, University College London, London, United Kingdom. Electronic address: Daniel.Kotz@med.uni-duesseldorf.de.
Jakob Manthey Centre for Interdisciplinary Addiction Research (ZIS), Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf (UKE), Martinistraße 52, 20246, Hamburg, Germany; Department of Psychiatry, Medical Faculty, University of Leipzig, Semmelweisstraße 10, 04103, Leipzig, Germany. Electronic address: j.manthey@uke.de.
Stephanie Klosterhalfen Institute of General Practice, Addiction Research and Clinical Epidemiology Unit, Medical Faculty of the Heinrich-Heine-University Düsseldorf, Germany. Electronic address: Stephanie.Klosterhalfen@med.uni-duesseldorf.de.
Paula Steinhoff Institute of General Practice, Addiction Research and Clinical Epidemiology Unit, Medical Faculty of the Heinrich-Heine-University Düsseldorf, Germany. Electronic address: Paula.Steinhoff@med.uni-duesseldorf.de.
Wolfgang Viechtbauer Department of Psychiatry and Neuropsychology, Mental Health and Neuroscience Research Institute, Maastricht University, the Netherlands. Electronic address: wolfgang.viechtbauer@maastrichtuniversity.nl.