Psychotic disorders increasingly diagnosed in younger Canadians

A new study suggests that people born more recently are being diagnosed with psychotic disorders (e.g., schizophrenia) more often and at younger ages compared with people born earlier. 

The study included over 12 million individuals who were born between 1960 and 2005 and followed them for new diagnoses of a psychotic disorder between 1993 and 2023. Over the study, 152,587 individuals were diagnosed with a psychotic disorder. Researchers from ICES, North York General, The Ottawa Hospital, and Bruyère Health Research Institute found that the rate of new diagnoses of psychotic disorders started rising for people born in the 1980s and later. For example, individuals born in 2000-2004 were estimated to have a 70 per cent greater rate of new diagnoses of psychotic disorders compared to those born in 1975-1979. The total number of people diagnosed with a psychotic disorder by the time they reached age 30 increased by 37.5 per cent higher for those born in 1990-1994 compared to 1975-1979. 

Psychotic disorders can have profound negative impacts on a person’s life, including their mental and physical health, education, work, and relationships. While some of the increases in psychotic disorder diagnoses in people born in the 1980s and 1990s may reflect improvements in care and early diagnosis, these patterns raise important concerns about generational changes in exposure to factors that increase the risk of psychotic disorders. 

We don’t yet know what’s driving these changes, and it’s likely there isn’t a single explanation. Understanding what’s behind this trend will be critical to prevention and early support.” 

Dr. Daniel Myran, Gordon F. Cheesbrough Research Chair in Family and Community Medicine, North York General and scientist at ICES and the Bruyère Health Research Institute

Risk factors associated with psychosis, including early life substance use and older-aged parents, may contribute to the rise of psychotic disorders. 

Key findings: 

• The incidence rate of people aged 14 to 20 diagnosed with a psychotic disorder increased by 60 per cent, from 62.5 to 99.7 per 100,000 individuals. 

• The total number of people diagnosed with a psychotic disorder by the time they reached ages 20 and 30 were 74.1 per cent and 37.5 per cent higher, respectively, for those born in 1990-1994 compared to 1975-1979. 

“While incidence and prevalence remain low, some international studies suggest that schizophrenia and other psychotic disorders are on the rise among young people, with an increased role of substance use, but this study is the first to examine recent birth cohorts in North America,” says Dr. Marco Solmi, Clinician Investigator, The Ottawa Hospital, Director of Research, Associate Professor and Chair in Evidence-based Mental Health, University of Ottawa, and co-author of the study. 

One of the limitations of the study was that people born in the 1960s and early 1970s who developed psychosis in early adulthood and subsequently did not interact with the health system were not included in the cumulative estimates. 

The study “Incidence of psychotic disorders by birth cohort: a population-based cohort study in Ontario, Canada” is in the February issue of CMAJ. 

ICES is an independent, not-for-profit research and analytics institute that uses population-based health information to produce knowledge on a broad range of healthcare issues. ICES leads cutting-edge studies and analyses evaluating healthcare policy, delivery, and population outcomes. Our knowledge is highly regarded in Canada and abroad and is widely used by government, hospitals, planners, and practitioners to make decisions about healthcare delivery and to develop policy. For the latest ICES news, follow us on BlueSky and LinkedIn: @ICESOntario 

North York General is one of Canada’s leading community academic hospitals with a vision to deliver World-Class Care, 24/7. Affiliated with the University of Toronto, our multi-site campus supports our diverse community through every stage and life-defining moment by providing a wide range of acute care, ambulatory and long-term care services. 

North York General is a member of the North York Toronto Health Partners, an Ontario Health Team that integrates local care with patients, primary care and community partners. 

Bruyère Health Research Institute conducts world-class research to maximize quality of life and shape the future health care. As part of an academic sciences centre, our research supports evidence-based care with a focus on aging and long-term care, palliative care, rehabilitation and recovery, and social accountability. To learn more, visit www.bruyere.org. 

The Ottawa Hospital is one of Canada’s top learning and research hospitals, where excellent care is inspired by research and driven by compassion. As the third-largest employer in Ottawa, our support staff, researchers, nurses, physicians, and volunteers never stop seeking solutions to the most complex health-care challenges. Our multi-campus hospital, affiliated with the University of Ottawa, attracts some of the most influential scientific minds from around the world. Backed by generous support from the community, we are committed to providing the world-class, compassionate care we would want for our loved ones. 

The University of Ottawa is powered by research. Located in Canada’s capital, we bring together energetic and creative scholars to tackle urgent global challenges and seize emerging opportunities. 

As one of Canada’s most innovative universities, we generate breakthroughs and discoveries that make a real difference in communities in Ontario, across Canada and around the world. Our thought leaders provide evidence-based insights that inform policy and support industry. 

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