Published on 14 March 2025

WeedCare – Canton of Basel-Stadt

The WeedCare study is examining the effects in public health terms of permitting regulated cannabis sales, compared to the present situation in which cannabis is available on the black market.

The main aim of the study is to evaluate the impact of regulated cannabis sales on the behaviour of cannabis users. In particular, it is to be investigated whether regulated cannabis sales at selected pharmacies in the canton of Basel-Stadt lead to a reduction of problematic cannabis use in study participants. The resulting scientific findings will provide a basis for discussion on a future responsible cannabis policy in Switzerland.

• Research Questions

  The main aim of the study is to investigate the impact on cannabis users of regulated cannabis sales at pharmacies in the canton of Basel-Stadt. Specifically, it will be assessed whether the provision of information and advice in the pilot trial improves cannabis use competency. For purposes of comparison, a control group will continue to purchase cannabis on the black market. In addition, it will be investigated whether an improvement in use competency leads to a reduction in problematic cannabis use. It will also be studied to what extent the THC:CBD ratio in the products used is associated with mental health.

• Legalisation model

  Commercial market
  Pharmacy sales

• Responsible organisation(s)

  Institution responsible for carrying out the study

  • Addictions Section, Basel-Stadt Department of Health (commissioning authority), www.bs.ch/sucht
    
  • University Psychiatric Clinics (UPK) Basel (institution responsible), www.upk.ch
  • University of Basel, Department of Clinical Research (institution responsible), www.dkf.unibas.ch

  Contact

  • Regine Steinauer
    Addictions Section
    Malzgasse 30
    4001 Basel
    [e-mail] / 061 267 89 00

• Canton(s)

  Basel-Stadt
  

• Commune(s)

  City of Basel
  

• Planned duration of the study

  September 2022 to January 2027
  

• Points of sale

  Pharmacies

• Study type

  • Randomised controlled trial (RCT)
  • Observational study
    

• Sample size

  • Planned total sample size N = 374

• Funder

  • Canton Basel-Stadt (funds)
  • Addictions Section, Canton Basel-Stadt Department of Health (services)
  • University Psychiatric Clinics Basel (services)
  • Psychiatrische Dienste Aargau AG (services)

• Links

  • https://weedcare-basel.ch/
  • Weed Care – Forschung zur Regulierung des Cannabiskonsums – DKF Basel
  • https://www.kofam.ch/en/snctp-portal/searching-for-a-clinical-trial/study/58583