CRYSTALWEED cannabis / Unsplash
CV NEWS FEED // Schizophrenia cases associated with cannabis use disorder have almost tripled since Canada legalized marijuana, a new study found.
The study, published Feb. 4, found that the percentage of schizophrenia cases linked to cannabis use disorder (CUD) in Ontario increased from 4% before legalization to 10% after.
The study included Ontario residents aged 14 to 65 who had received medical care for CUD before their diagnosis of schizophrenia.
CUD is “defined as a person being unable to stop using cannabis despite it causing serious social and health problems,” according to the Canadian newspaper Ottawa Citizen.
The study analyzed data based on three policy periods between 2006 and 2022: before legalization, after medical expansion, and after non-medical legalization.
Medical cannabis has been legal in Canada since 2001 for individuals with chronic medical conditions.
In 2014, eligibility expanded to anyone with a doctor’s authorization stating they would benefit therapeutically. Recreational cannabis was legalized in 2018.
Study co-author Dr. Daniel Myran said in a statement: “I think the concern is that daily cannabis use has really increased in the last 15 years and at the same time the potency of cannabis has rapidly risen. Both are what prior literature says are major risk factors for psychosis and schizophrenia.”
“The tripling of schizophrenia cases associated with a cannabis use disorder over the past 17 years and rising cases of psychosis underscores the urgent need for targeted prevention strategies, particularly for younger populations who appear to be at the greatest risk,” he added.
Another recent study in Ontario found that individuals hospitalized for CUD faced a significantly higher risk of death than the general population.
The authors of the study acknowledged several limitations, including the lack of access to detailed information, such as the type or frequency of cannabis use.
Still, the authors wrote, “Although cannabis use disorder may not be directly responsible, our findings highlight a growing segment of the population who are at elevated risk of death and may benefit from preventative measures.”
