Smoking weed healthier with the city of Zurich: Authorities praise their own cannabis study

Those who purchase cannabis in Zurich often do not do so in secret and secretly, but with official approval from the authorities. Marijuana can be purchased against ID at defined locations such as pharmacies, social clubs or drug information centers.

This has been made possible for around three years by the “Züri Can – Cannabis with Responsibility” study. It is carried out by the city of Zurich in collaboration with the Zurich University Psychiatric Hospital. The study aims to find out how health and consumption change when stoners move from the illegal market to regulated, non-commercial access.

On Tuesday, the municipal health services drew up an initial interim assessment based on data from two years. The balance sheet reads positively euphoric. Participants would have less problematic consumption, it says.

This means a less strong dependence, based on the frequency of smoking weed and the strength of the cannabis. Consumers also suffered from fewer anxiety and sleep disorders. They also had fewer physical complaints and their depression levels remained stable.

According to the researchers at the University of Zurich, the improvements can be attributed to the accompanying damage reduction measures. Such measures include advice and specialist staff, clear THC limits and strict purchase limits. The tenor of the city: The cannabis project reduces the health problems of stoners.

However, the central findings are based on self-reports from the 3,100 participants. This is true in addiction research most common method to collect data on substance use – but is still susceptible to recall bias, expectancy effects and social desirability.

Black market still exists

Barbara Burri from the municipal health services is the project manager of “Züri Can”. She sees no danger of distorted information, she tells the NZZ: The data is collected completely anonymously. The participants would therefore have no incentive to present themselves as particularly positive about the study. The answers would have no consequences for the participants.

Burri also does not see another form of distortion, namely that only particularly responsible or health-conscious stoners could take part in the study and stay with it: the field of participants is very heterogeneous. Around a quarter of the people initially had problematic consumption, i.e. consumed heavily and for a long time. The proportion with a cannabis disorder has fallen to around a fifth.

However, the study does not provide an answer to all questions. It is still not clear to this day how much the black market in Zurich is actually being undermined. Barbara Burri says: “We are aware that this cannot displace the black market.” But you can have an impact. To date, around 1,000 kilograms of cannabis have been given to the participants, which corresponds to a market price of 10 million francs. This quantity was withdrawn from the black market.

The Swiss do it differently than the USA

Zurich is not the only place where cannabis studies are taking place. According to Barbara Burri, the results in Bern, Biel, Basel, Geneva and Lausanne are everywhere similar to those in Zurich. The study results are intended to support the discussion about the planned cannabis products law.

But isn’t Zurich running the risk of overestimating the positive effects and thus scientifically ‘glossing over’ legalization?

Project manager Barbara Burri says it’s not about legalization, but about strict regulation with a health-oriented approach. The non-commercial aspect of the project is crucial.

The Swiss approach differs from that in the USA. Because legal cannabis sales are about profits, stronger and unlimited products are sold. Burri is convinced that the results here can one day be transferred to a broad, national law.

For this purpose, people in Zurich continue to smoke weed and collect data. In March, the city parliament extended the study until October 2028. 800,000 francs were donated for this.