A recent study has revealed that the legalization of cannabis in Switzerland has led to a reduction in problematic consumption, particularly among individuals who also use other drugs. This research is part of Switzerland’s pioneering adult-use cannabis pilot program, known as the Weed Care study, which began in January 2023 in Basel.
The Weed Care study is a collaborative effort involving the Addiction Department of the Canton of Basel-Stadt, the University of Basel, the University Psychiatric Clinics Basel, and Psychiatric Services Aargau. Its primary goal is to assess the impact of legal cannabis supply on consumption patterns and mental health, contributing to the development of evidence-based cannabis regulations in Switzerland.
In the study, approximately 370 participants were divided into two groups: one group had access to legal cannabis from nine participating pharmacies and received counseling, while the control group continued to use cannabis obtained illegally. Researchers collected data on participants’ consumption habits and mental health through regular questionnaires.
The findings, published in the journal *Addiction*, indicate a slight decline in problematic consumption among those with legal access to cannabis. Problematic consumption is defined as use that exacerbates health, social, or psychological issues, even without classic dependency. Notably, individuals who used other drugs alongside cannabis experienced a marked decrease in problematic cannabis use. Dr. Lavinia Baltes-Flückiger, the study’s deputy head and lead author, noted that this is the first controlled, randomized study to compare legal versus illegal cannabis access.
After six months, researchers found no significant differences in depression, anxiety, or other mental health symptoms between the two groups. Following this period, the control group transitioned to legal access through pharmacies. An interim assessment after two years showed improved mental health in approximately 300 participants still involved in the study. Professor Marc Walter, head of the study, stated, “Legal access eases the burden on consumers.”
The Weed Care study is one of seven adult-use pilot programs currently active in Switzerland. Preliminary findings from these programs, released by the government earlier this year, indicated a trend towards lower-risk consumption behaviors and a destigmatizing effect for those obtaining cannabis through pharmacies.
In February, Swiss policymakers approved a draft proposal to create a fully commercial adult-use cannabis market. This draft, which would permit citizens to legally grow, buy, possess, and consume cannabis, received strong support from the National Council’s Social Security and Health Committee, passing with a vote of 14 to 9.
Overall, the findings of this research contribute valuable data to the ongoing discussion about cannabis legalization and its implications for public health and safety.
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