Publications

First Interim Report on the Evaluation of the Act on the Handling of Cannabis for Non-Medical Use (EKOCAN) (Summary available in English; full text in German)

Here you can find study protocols for various sub-areas of the project.
They document, among other things, the planned data collection and/or analysis steps for different data sources.

Study protocol for the survey of cannabis users and non-users (in German)

Correlates of driving under the influence of cannabis: a latent class analysis

Schranz, A., Verthein, U., Rosenkranz, M., Knoche-Becker, A., & Manthey, J. (2025). J Safety Res, 95, 330–337. https://doi.org/10.1016/j.jsr.2025.10.012

What proportion of people who use cannabis in Germany have spoken with their general practitioner about their consumption? A repeated cross-sectional representative population survey

Borchardt, B., Klosterhalfen, S. & Kotz, D. (2025). J Cannabis Res 7, 76. https://doi.org/10.1186/s42238-025-00329-0

“Those pot heads” – perceived external stigma and self-stigma among cannabis users in Germany: prevalence and associations with socio-demographics, cannabis use patterns and psychological distress

Rosenkranz, M., Schranz, A., Verthein, U., Schomerus, G., Speerforck, S., & Manthey, J. (2025). J Cannabis Res, 7, 66. https://doi.org/10.1186/s42238-025-00328-1

Germany's cannabis act: a catalyst for European drug policy reform?

Manthey, J., Rehm, J., & Verthein, U. (2024). Lancet Reg Health Eur, 42, 100929. https://doi.org/10.1016/j.lanepe.2024.100929

Cannabis Use in Germany: Frequency, Routes of Administration, and Co-use of Inhaled Nicotine or Tobacco Products

Kotz, D., Kastaun, S., Manthey, J., Hoch, E., & Klosterhalfen, S. (2024). Dtsch Arztebl International, 121(2), 52–57. https://doi.org/10.3238/arztebl.m2023.0237