Overview
- A CMAJ analysis of about 12.2 million Ontarians born from 1960 to 2009 identified 152,587 psychotic disorder diagnoses across 1993 to 2023.
- Annual incidence among 14–20 year‑olds rose roughly 60% from 62.5 to 99.7 per 100,000 between 1997 and 2023, with increases concentrated in recent birth cohorts.
- People born in 2000–2004 had an estimated 70% higher rate of new diagnoses than those born in 1975–1979, and cumulative diagnoses by age 30 were 37.5% higher for the 1990–1994 cohort versus 1975–1979.
- Expanded early‑psychosis programs likely improved detection, yet researchers say better ascertainment does not fully explain the cohort pattern.
- Substance use is flagged as a leading possible contributor alongside social and developmental factors, with similar cohort signals reported in Denmark and Australia and calls for bolstered early‑intervention capacity.