The proportion of new cases of schizophrenia associated with a cannabis use disorder has risen from 4% pre-legalization to 10% after cannabis legalization in Ontario, according to new research.

A new Canadian study shows a tripling of schizophrenia cases linked to cannabis use disorder since the country legalized it.

Two new studies led by Ottawa researcher Dr. Daniel Myran link higher rates of death as well as “concerning increases” in new schizophrenia diagnoses to cannabis use disorder. One study found that cases of schizophrenia associated with cannabis use disorder almost tripled in Ontario between 2006 and 2022,

Two new Canadian studies are the largest to date looking at death rates and psychosis associated with cannabis use disorder.

New schizophrenia cases in Ontario, Canada have nearly tripled since cannabis was legalised in 2015, according to a large-scale study. In just under two decades, the number of new cases rose from four per cent to over 10 per cent, the researchers said.

Heavy weed use may be far more dangerous than people realize, according to a pair of studies published in JAMA Network Open.

The proportion of new schizophrenia cases linked to cannabis use has nearly tripled in almost two decades, increasing gradually as access to the drug was expanded for medical and later recreational use, according to new population-based research.