19 March 2026

Positive results after three years of "Weed Care"

The "Weed Care" pilot project on regulated distribution of cannabis products has shown positive influence on the consumption behavior and mental health of study participants over the first three-year period.

As part of the "Weed Care" pilot project, cannabis products have been sold legally in selected pharmacies in the canton of Basel-Stadt since January 2023. This randomised controlled intervention study with a subsequent observation phase is investigating how regulated access to cannabis affects the consumption behavior and well-being of users. Additionally, it evaluates what insights could be gained for the future cannabis policy in Switzerland.

Cannabis use is decreasing

After three years, the study results show that study participants have reduced their problematic use of cannabis, particularly the use of joints with tobacco. Monthly purchase quantities remained stable, and lower-risk products such as oil, vapes and spray quickly became popular since their introduction as part of the study extension in August 2025.

Positive impact on mental health

Mental health also developed positively over the duration of the study: depressive, anxiety and psychosis-like symptoms as well as the use of other substances decreased. The study team attributes the improvements to the elimination of illegality, to the availability of destigmatising advice situations in pharmacies and to safe, declared products, among other things.

Stable participation

Interest in regulated offers remains high: around 70 percent of the original study participants are still actively involved. The choice of products and their quality is rated positively by the majority. The study management sees the interim results as a clear signal that permanent legal regulation of cannabis would be sensible.

Weed Care is a joint project of the Basel-Stadt Department of Health, the University Psychiatric Clinics, Psychiatric Services Aargau and the Department of Clinical Research, in whose outpatient study center at the USB the WeedCare participants were supervised. A final report is expected in 2027.