Commercial cannabis markets increase use and health risks

A major international study has found that decriminalizing cannabis does not lead to increased use, but the creation of commercial, for-profit markets is linked to higher consumption, greater addiction, and more hospital admissions for psychosis. The findings, published in The Lancet Psychiatry on June 17, 2026, offer the most comprehensive global analysis to date on the outcomes of different cannabis policies.

The systematic review, led by researchers at the University of Bath in the United Kingdom, analyzed data from across the Americas, Europe, Africa, Australia, New Zealand, and Asia from 2000 to 2025. It draws a sharp distinction between policy approaches. Jurisdictions that have only decriminalized personal possession or implemented strictly regulated, non-commercial legalization models, such as Uruguay, showed little evidence of increased cannabis use or associated psychiatric harm.

In contrast, regions that have embraced full commercial legalization, notably in Canada and many U.S. states, experienced significant changes. These markets saw increased sales and consumption, a rise in the potency of cannabis products, and higher rates of cannabis use disorder. The study...