Cannabis pilot in the canton of BL (‘Grashaus Projects’)

Cannabis remains the most widely consumed illegal substance in Switzerland, despite its prohibition, and consumption continues to increase. New approaches to regulating the use of cannabis are therefore essential. The Ordinance of 31 March 2021 on Pilot Trials under the Narcotics Act (BetmPV) regulates the requirements for conducting scientific pilot trials with narcotics of the cannabis effect type. This came into force on 15 May 2021 and allows pilot trials to be conducted in Switzerland with the controlled sale of cannabis for recreational (non-medical) purposes, which are scientifically monitored in order to generate new knowledge regarding regulated cannabis dispensing models in Switzerland.

The aim is to investigate the effects of a regulated cannabis dispensary (‘specialised shop’) selling THC-containing study cannabis products for non-medical purposes (‘recreational purposes’). The primary aim is to investigate whether the cannabis consumption behaviour of the participants develops in the direction of lower-risk, harm-reducing consumption and whether there is a reduction in problematic cannabis consumption. In addition, other target variables are analysed, e.g. how the physical or mental health of the participants develops, or how their consumption skills or the consumption of other substances develops.

This is a naturalistic study design in which participants can obtain study cannabis at two specially designated sales and dispensing points (branches in Allschwil and Liestal). A central component of these dispensaries is the harm-reduction counselling provided by the trained sales staff and the teaching of consumption skills for low-risk consumption. Participants complete questionnaires and follow-up surveys on an ongoing basis during their participation (usually every 6 months), which ask them about their consumption behaviour, their health and other aspects relevant to the study. Interested persons must fulfil certain inclusion criteria for participation (e.g. no pregnancy, proven cannabis use, age >= 18, place of residence in one of the approved municipalities in the canton of BL). An online screening checks eligibility for participation in advance. Prior to inclusion in the study, an individual eligibility assessment interview will take place with the study nurse (qualified nurse HF Psychiatry). The health of the participants is automatically monitored by various screening instruments and our study nurse. Participants are also integrated into the study doctor's health network.

The findings of the accompanying study - together with the findings from other cannabis pilot trials - will serve as a basis for making decisions on the long-term regulation of cannabis (sales) in Switzerland.