In 2018, the Cannabis Act legalized recreational cannabis across Canada, making it the second country to pass such legislation, after Uruguay. Now, Canadians as young as 18 can purchase the drug—even though a growing body of research shows that cannabis use is particularly dangerous to the adolescent brain, as it negatively affects neurocognitive performance, brain development, and brain functioning.
In July 2023, a group of Canadian researchers added to that growing body of research. They published a study in the peer-reviewed Molecular Psychiatry that linked cannabis legalization to an increase in psychotic disorders. The authors included Daniel T. Myran, a public health and preventative medicine physician with an interest in addiction medicine, and Michael Pugliese, a clinical research coordinator at the University of Ottawa. (They previously co-wrote a study on the link between cannabis and anxiety disorders.)
In this study, the researchers looked at data on emergency department visits in Ontario, Canada during three distinct time periods:
- Pre-legalization (January 2014–September 2018)
- Legalization with restrictions (October 2018–February 2020)
- Commercialization (March 2020–September 2021)
What they found was that there were 6,300 total emergency department visits for cannabis-induced psychosis. And after commercialization, there was an immediate increase in visits related to cannabis-induced psychosis—especially for young adults aged 19–24.
Cannabis-induced psychosis is a serious health crisis. It can cause symptoms like hallucinations, dissociation, and disorganized thinking—and at its worst, schizophrenia and suicide. Commercializing cannabis makes the drug readily available to youth who may not understand the implications of using marijuana. To protect our youth, we need to do more to educate them and lawmakers about the real effects of cannabis.
To read the full study, visit this page.