A groundbreaking study from Switzerland suggests that regulated cannabis access through pharmacies might help reduce problematic cannabis use—especially for people who also use other drugs. The research, published in the journal Addiction, is the first randomized controlled trial of its kind, offering much-needed evidence in a field dominated by observational studies.
Many countries are debating whether legalizing recreational cannabis does more harm than good. Until now, most data came from regions where legalization happened without much control over how cannabis was sold or used. This made it hard to understand what really caused changes in use or mental health outcomes.
Swiss researchers aimed to answer that question more clearly by conducting a tightly controlled trial under Switzerland’s unique pilot law that allows limited legal cannabis access for research purposes.
Legal vs. Illegal: The Study Design
Researchers in Basel recruited 378 regular cannabis users and split them into two groups. One group could legally buy cannabis from nine pharmacies that followed strict rules:
Limits on THC (the chemical that gets you high)
Price adjustments based on THC strength
Product labeling with health info
Optional counseling and educational materials
The other group continued to get cannabis illegally, as they normally would.
After six months, both groups answered questions about their drug use and mental health. The main focus was on how many showed signs of cannabis misuse using a standard survey called the CUDIT-R.
What Did the Study Find About Regulated Cannabis Access?
While the overall difference in misuse scores between the two groups was small (10.1 in the legal group vs. 10.9 in the illegal group), researchers found something important when they looked deeper.
Among people who used other drugs in addition to cannabis, those in the legal access group showed a greater drop in cannabis misuse scores—almost two points lower than those buying cannabis illegally. That’s a meaningful change that could indicate safer patterns of use.
People in the legal access group also had support: they could ask pharmacy staff questions and receive accurate health information. This kind of ongoing contact may have played a role in reducing risky behaviors, especially for those facing more complex substance use challenges.
What Didn’t Change?
Some things stayed the same across both groups. There were no major differences in:
Total amount of cannabis used
Symptoms of depression, anxiety, or psychosis
Alcohol or other drug consumption
This suggests that simply having access to legal cannabis doesn’t automatically lead to more or less use—but how cannabis is provided may influence behavior for people at higher risk.
Interestingly, about half the participants in the legal group still used cannabis from the illegal market. This crossover made the study results a bit less clear but didn’t change the overall findings.
Safety and Limitations
No serious mental health issues were linked to the legal cannabis. Serious side effects were rare and spread evenly across both groups.
Still, researchers caution that this was a short-term study with some limitations:
Most participants were men
People with severe mental illness were excluded
Outcomes were based on self-reported data
Participants knew which group they were in, which could influence their answers
Future research will need to look at long-term effects and whether different legal models—like cannabis social clubs or dispensaries—produce better results.
Why This Matters for Interventional Psychiatry
For clinicians and researchers in interventional psychiatry, this study points to a promising trend: when cannabis is treated as a public health issue rather than a criminal one, outcomes may improve. Especially for patients with co-occurring substance use disorders, regulated cannabis access could be one part of a larger harm reduction strategy.
As new therapies like neurofeedback, light therapy, and biofeedback evolve, understanding how legal environments interact with mental health treatment is essential. This kind of evidence-based cannabis policy might one day work alongside emerging therapies to support better patient care.
Read more about the brain at https://interventionalpsychiatry.org/
Citations
Baltes-Flueckiger, L., Steinauer, R., Meyer, M., et al. (2025). Effects of legal access versus illegal market cannabis on use and mental health: A randomized controlled trial. Addiction. https://doi.org/10.1111/add.16428
PsyPost. (2025). Researchers uncover causal evidence that cannabis legalization reduces problematic consumption. https://www.psypost.org/2025/05/researchers-uncover-causal-evidence-that-cannabis-legalization-reduces-problematic-consumption-225983
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This article was produced using a combination of editorial tools, including AI, as part of our content development process. All content is reviewed by human editors before publication.