Psychosis more common in recent generations in Ontario, study says
Rates of psychosis are rising dramatically in more recent generations, according to a new Ontario-based study that is raising questions about what is behind the numbers.
The study looked at 12.2 million people born in Ontario between 1960 and 2009. Over the study period, rates of new diagnoses of psychotic disorder, including schizophrenia, increased by 60 per cent in people aged 14 to 20 years old between 1997 and 2023. The increases occurred in more recent birth cohorts. People born between 2000 and 2004, for example, were estimated to have a 70-per-cent greater rate of diagnoses of psychotic disorders than those born between 1975 and 1979.
The study was published in the Canadian Medical Association Journal.
Dr. Daniel Myran, a physician and scientist at the Bruyère Health Research Institute, the Institute for Clinical Evaluative Sciences (ICES) and North York General, saw signs that psychosis rates had been going up in younger people during earlier research evaluating Canada’s cannabis policy. Still, he was surprised by the scale of the increase uncovered in the just-published research.
The findings, he said, raise important questions about the possible causes and consequences of increasing numbers of psychotic disorder diagnoses.
People with psychotic disorders experience substantial rates of illness and the risk of premature death and often require substantial health services and social support, Myran said.
He said there were some constraints to the research, including that the same amount of data was not available for older birth cohorts as for those born after the mid-1990s, but it was clear there had been a meaningful increase in people being diagnosed with psychosis in recent decades.
Part of the increase, Myran said, could be attributed improvements in access to care in Ontario beginning in the early 2000s.
Ontario has well-established early psychosis intervention programs that began as a grassroots effort and expanded rapidly beginning in the early 2000s. Ottawa, through The Ottawa Hospital, is home to one of the programs called On Track: First Episode Psychosis Program, which has been operating for the past 20 years.
Myran said those programs could be responsible for part of the increase in diagnoses at young ages in Ontario, suggesting the health system might be doing a better job of identifying psychosis, but that likely does not tell the entire story, he said.
Myran said there were likely multiple factors contributing to the trend.
“It raises concerns that there are some social or environment changes that are occurring that are causing an increase.”
More research is needed, he said, to try to understand the factors behind the numbers.
“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.”
Myran, who has studied links between substance use and psychosis, said substance use was a “leading possibility” in rising rates of psychosis among more recent generations in Ontario.
“The use of substances, especially earlier in life, is associated with the development and worsening of psychotic disorders and substance use in Canada has risen over the past two decades,” he said.
The study was conducted by researchers from ICES, The Ottawa Hospital Research Institute, Bruyère Health Research Institute and North York General.
Related
Our website is your destination for up-to-the-minute news, so make sure to bookmark our homepage and sign up for our newsletters so we can keep you informed.
