0 1
Canada’s legalization of cannabis has been linked to an increase in schizophrenia cases, new research shows.
Over a 16-year time period — spanning before and after legalization of cannabis for medical and recreational use — the number of new cases of schizophrenia associated with cannabis use disorder (CUD) in Ontario nearly tripled after legalization, investigators found.
“There has been a lot of research on the association between cannabis use and schizophrenia and one of the main concerns about cannabis legalization is whether it might result in increases in cases of schizophrenia,” study investigator Daniel Myran, MD, MPH, with Ottawa Hospital Research Institute, Ottawa, Ontario, Canada, told Medscape Medical News .
“We found that there have been concerning increases over time in the percentage of people with a new schizophrenia diagnosis who had received care for a cannabis use disorder before their diagnosis,” Myran added in a news release.
The study was published online on February 4 in JAMA Network Open . A Growing Public Health Challenge
The researchers evaluated the electronic medical records of more than 13.5 million residents of Ontario (mean age, 39 years) without a history of schizophrenia and considered three policy time periods between 2006 and 2022 — before legalization (January 2006 to November 2015), after legalization of medical cannabis (December 2015 to September 2018), and after legalization of nonmedical cannabis (October 2018 to December 2022).
In total, 118,650 individuals (0.9%) had an emergency department visit or hospital stay for CUD. During the study period, 10,583 (9.0%) of individuals with CUD developed schizophrenia compared with 80,523 (0.6%) of individuals without CUD.
After legalization of cannabis, the number of people in Ontario who required hospital care for CUD jumped by 270%, from about 1.3 in every 1000 people before legalization to 4.6 after legalization, results showed.In addition, the proportion of new cases of schizophrenia associated with CUD increased from 3.7% (95% CI, 2.7%-4.7%) before legalization to 10.3% (95% CI, 8.9%-11.7%) after legalization, with young men aged 19-24 years most likely to be affected.“Our study highlights the growing public health challenge posed by the combination of increasingly high-potency cannabis and rising […]
Has Legalized Cannabis Led to a Surge in Schizophrenia Cases?
