A recent study suggests a possible link between increased cannabis use and a rise in psychosis diagnoses among young individuals.
Researchers examined data from 12 million people, born between 1960 and 2009 in Ontario, Canada, from 1992 to 2023.
The alarming increase in psychosis diagnoses has led to speculation that it may be connected to higher consumption of substances such as cannabis, hallucinogens, and stimulants.
Published in The Canadian Medical Association Journal, the study revealed a 60 percent rise in psychotic disorder diagnoses among individuals aged 14 to 20 from 1997 to 2023, while diagnoses in other age demographics declined.
Compared to those born in the late 1970s, the younger cohort was found to be twice as likely to receive a psychotic disorder diagnosis.
Researchers explored several factors contributing to this trend in young people, including neonatal health and advanced paternal age. Cannabis use was also considered a potential factor.
Dr. Daniel Myran, one of the study’s authors, participated in the research out of concern that cannabis legalization might intensify psychosis diagnosis rates.
“I was expecting to see some increases in these younger folks, but I was quite surprised by the scale,” he told The New York Times.
He further explained, “I think that there is a group of individuals who develop psychosis because of substance use, who in its absence would not have.”
“The interesting question is, how much of psychosis is caused by a modifiable substance use? Are these edge scenarios, where it’s pretty rare? Or is it actually quite frequent?”
Only 0.9 percent of the population was diagnosed with a psychotic disorder during the 31-year study period.
In 2024, the Canadian Cannabis Survey reported that 41 percent of Canadians aged 16 to 19 used cannabis at least once a year, reflecting a five percent increase since its legalization in 2018.
The study explored schizophrenia, identified by delusions, among other diagnoses.
The largest increase was seen in cases of ‘psychosis not otherwise specified,’ indicating the presence of psychosis without a formal schizophrenia diagnosis.
While Dr. Myran noted the absence of a definitive cause linking cannabis to the increase, he hypothesized that substance use during adolescence might cause ‘structural changes’ in the brain.
He stated: “You go to the idea that neurons that fire together wire together. Your brain is quite plastic, and if we have substance use that’s causing hallucinations, if you have ongoing activation and firing and that kind of stuff, it can change your brain.”
If you are seeking supportive and confidential advice about drugs, you can contact American Addiction Centers at (313) 209-9137 at any time, or reach out through their website.