A Lancet Regional Health study comparing Germany and Austria found no significant short-term effects of German cannabis legalization on either cannabis use prevalence or driving under the influence of cannabis, though one in five DUIC episodes involved combining cannabis with alcohol or other drugs.
European policymakers considering cannabis reform, traffic safety researchers, and road safety advocates.
No significant increase in cannabis use or DUIC 8 months after German legalization
What the researchers found
German cannabis use rose from 12.1% to 14.4%, but this did not significantly differ from Austrian trends (DiD OR 1.18, 95% CI 0.95-1.48). Among monthly+ users, DUIC decreased slightly from 28.5% to 26.8% with no significant difference from Austria (DiD aOR 0.68, 95% CI 0.27-1.68). DUIC combined with alcohol/drugs (DUIC+) accounted for 21.5% of episodes and was most common among weekly users.
Why it matters
Germany is the largest European country to legalize cannabis, making its experience crucial for other European nations considering reform. The finding of no significant short-term increase in stoned driving addresses one of the primary safety concerns about legalization, though the 21.5% rate of combined cannabis/alcohol DUIC episodes is concerning.
The numbers in context
Germany: use 12.1% to 14.4%. Austria control. DiD for use: OR 1.18 (NS). DiD for DUIC: aOR 0.68 (NS). DUIC+: 21.5% of episodes. DUIC without other substances most common among daily users. DUIC+ most common among weekly users.
How the study worked
Cross-sectional population surveys in Germany and Austria before (November-December 2023) and after legalization (November 2024-January 2025). Difference-in-differences analysis using Austria as control. Cannabis use assessed in adults 18-64 (Germany: ~16,000; Austria: ~4,200). DUIC assessed among monthly+ users.
What this study cannot tell us
Only 8 months post-legalization; effects may take longer to emerge. No legal commercial sales were operating during the study period (only possession and cultivation were legal). Self-reported DUIC may underestimate true prevalence. Austria is an imperfect control (cultural and policy differences).
How to read the evidence
Published in Lancet Regional Health with difference-in-differences design using Austria as control, though limited by short follow-up and pre-commercial-sales timing.
When this study was published
Published in 2026, covering November 2023 to January 2025.
The bigger picture
Published in Lancet Regional Health Europe, this study provides the first rigorous evaluation of Germany's cannabis reform using Austria as a natural control group. The null findings for both use and DUIC at 8 months are consistent with Canadian and US state-level data showing that legalization effects on use and driving are slow to materialize, if they do at all.
Questions still open
- Will use and DUIC increase once commercial sales begin? Is the 21.5% DUIC+ rate (combined with alcohol/drugs) already a public health concern? How does the new THC driving limit (established August 2024) affect behavior?
Common questions
Did more people drive stoned after German legalization?
Why use Austria as a comparison?
Read the original research
Short-term effects of cannabis legalisation in Germany on driving under the influence of cannabis: a difference-in-differences analysis using Austria as a control.
The Lancet regional health. Europe, 63, 101593
Citation
Schranz, Anna; Knoche-Becker, Anja; Rosenkranz, Moritz; Verthein, Uwe; Manthey, Jakob. (2026). Short-term effects of cannabis legalisation in Germany on driving under the influence of cannabis: a difference-in-differences analysis using Austria as a control.. The Lancet regional health. Europe, 63, 101593. https://doi.org/10.1016/j.lanepe.2026.101593