Schizophrenia is a serious but treatable illness that develops in 1 in 4 individuals with 22q. We are world leaders in helping to understand and optimally treat it, so we are interested in trends related to schizophrenia in the general population.
Recently, a group of researchers studied health records from more than 12 million people in Ontario who were born between 1960 and 2009. They found that schizophrenia and other illnesses where people are out of touch with reality are being diagnosed more often in people born in recent years. Over the past 30 years, diagnoses of these illnesses increased by 60% in young people aged 14 to 20. The incidence rates (when the illness started) did not change much for adults aged 21 to 50.
Doctors do not know the exact reason why psychotic disorders are increasing in young people. One possible reason may be the use of cannabis, also called “weed.” Studies over several decades have shown a link between cannabis and an increasing risk of developing schizophrenia.
Our clinic team advises patients not to use cannabis in any form, including smoking, vaping, or edibles. Cannabis can increase the risk of learning problems, heart problems, anxiety, and schizophrenia. It can also cause stomach problems, such as belly pain, nausea, and vomiting, which can be severe. If you have questions or concerns, please make an appointment to talk with your doctor.
References
Incidence of psychotic disorders by birth cohort: a population-based cohort study in Ontario, Canada Myran DT, Gibb M, Pugliese M, et al. CMAJ February 02, 2026 198 (4) E118-E127 DOI: https://doi.org/10.1503/cmaj.250926
Psychosis rates climb among young people in Ontario, researchers find CBC News, February 2, 2026
More about Psychotic Disorders and Recreational Drugs
The International 22q11.2 Foundation
- Psychotic Disorders (includes schizophrenia; Part of Health Conditions Explained)
The Dalglish Family 22q Clinic
- Psychiatry (Part of “Features in Adults with 22q11.2 Deletion Syndrome”)
- Recreational Drugs
- Emergency Department visits for cannabis use were related to a later healthcare visit for an anxiety disorder
- Schizophrenia Cases Related To Cannabis Use Went Up Almost 3 Times In 17 Years