A new Ontario study analyzing 30 years of health data suggests a strong correlation between rising cannabis use and increased rates of psychotic disorders among youth aged 14 to 20. While not the sole cause, experts identify substance use, particularly cannabis, as a leading factor in the 60% surge in diagnoses within this age group.
Key Takeaways:
- Diagnosis Surge: Psychotic disorder rates in 14-20 year-olds rose by 60%.
- Cannabis Link: Experts suspect cannabis and synthetic drugs are major contributors.
- Vulnerable Group: Adolescents are at higher risk for long-term mental health effects.
- Widespread Use: Over one-third of young Canadian adults reported using cannabis in 2023.
Researchers from North York General Hospital have confirmed a significant rise in psychotic disorder diagnoses among Ontario youth. This development occurs amidst the widespread legalization and use of recreational cannabis in Canada, directly resulting in renewed warnings from health experts about the drug's impact on adolescent brains.
A 60% Increase in Youth Psychosis
The study, published in the Canadian Medical Association Journal (CMAJ), examined health data from over 12 million Ontario residents born between 1960 and 2009. The findings were stark: while rates of psychotic disorders like schizophrenia remained stable or declined for those aged 21 to 50, they skyrocketed for the younger demographic.
Dr. Daniel Myran, a lead researcher, noted that the annual rate of diagnoses for those aged 14 to 20 jumped by 60% over the 30-year period. Specifically, the rate rose from 62.5 cases per 100,000 people in the 1990s to nearly 100 cases per 100,000 by the study's end.
The Cannabis Connection
While Dr. Myran stated there isn't a single explanation, he pointed to substance use—including cannabis, stimulants, and hallucinogens—as a "leading possibility." Ottawa Hospital psychiatrist Sarah Brandigampola echoed this, stating, "In males, we’re seeing a younger age of onset and a stronger correlation to cannabis use."
Health experts warn that cannabis is more dangerous than commonly perceived, especially for developing minds. Short-term effects like paranoia and confusion can evolve into long-term consequences.
| Short-Term Risks | Long-Term Risks |
|---|---|
| Anxiety & Panic | Memory Loss & Learning Impairment |
| Paranoia | Chronic Depression |
| Impaired Motor Coordination | Development of Psychotic Disorders |
Widespread Usage Post-Legalization
Since the legalization of recreational cannabis in 2018, usage rates have remained high. A StatsCan report reveals that in 2023, more than one-third of adults aged 18 to 24 reported using cannabis in the previous year. Furthermore, about 1 in 10 young adults use it daily or almost daily.
While the cannabis industry generates significant revenue—$1.9 billion for federal and provincial governments in 2022/2023—the potential mental health costs for the younger generation are becoming increasingly apparent.

