A striking observation based on 12 million files
Do you feel like there’s more and more talk about mental health among young people? It’s not just an impression. A massive study has just put precise figures on this perception. Imagine: researchers looked at the records of 12.2 million people born in Ontario between 1960 and 2009. That’s huge. Published Monday in the Canadian Medical Association Journal, the results are clear. From this mass of data, 152,587 people were diagnosed with a psychotic disorder, such as schizophrenia. But what is most surprising is the trend over time. Dr. Daniel Myran, who holds the Gordon F. Cheesbrough Research Chair at North York General Hospital, is categorical: since the 1980s, each new generation seems to have more cases of psychosis than the previous one. Generally, in Canada, it is agreed that the incidence of these disorders is stable, affecting about 1 to 2% of the population. So why the alarm bells today? Because the average hides enormous disparities depending on age.
Young people more affected, older people spared
This is where the figures become staggering. Between 1997 and 2023, incidence rates among adolescents and young adults aged 14 to 20 jumped by 60%. In concrete terms, this represents an increase from 62.5 cases to 99.7 cases per 100,000 people. The average age of diagnosis has also fallen, from 25.4 to 23.2 in the most recent cohorts. But if the numbers are rising among young people, why do we say that the overall situation is stable? That’s the paradox. Among adults, the numbers are plummeting. Take a look: rates have fallen by 32.6% among 21-30 year olds, 62.0% among 31-40 year olds, and 33.6% among 41-50 year olds.
Dr. Myran explains that older cohorts are actually masking the increase among younger people. This view is shared by Dr. Luigi De Benedictis, a psychiatrist and researcher at the University of Montreal, who did not participate in the study. In his view, the aging of the population prevents us from seeing this increase in prevalence with the naked eye. Yet the evidence is there: for those born between 1990 and 1994, the number of diagnoses at age 30 has risen by 37.5% compared to those born between 1975 and 1979.
Cannabis and diagnosis: what has changed?
How can such a shift be explained? Dr. Luigi De Benedictis cautiously sums up the situation: these figures are not necessarily worrying, but they are not reassuring either. It is important to understand why.
First, medicine has changed. Over the past 20 to 25 years, detection has improved and become earlier. Early intervention programs are more accessible and diagnostic criteria have been broadened. This « skews the results a little, » admits the psychiatrist. But for Dr. Myran, this is not enough to explain everything.
We also need to look at our lifestyles. The use of psychoactive substances—cannabis, stimulants, hallucinogens, synthetic drugs—is being singled out. It is important to note that cannabis does not necessarily « create » psychosis from scratch, but it can cause it to appear earlier, says Dr. De Benedictis. This is especially true since the products have become much more powerful. Dr. Myran insists that this phenomenon did not begin with the 2018 legalization, but was already present long before that. He regrets that there is a lot of talk about overdoses, but not enough about these psychiatric consequences.
The city and the age of the parents are factors
There is no single explanation, warns Dr. Myran. It is a combination of social and environmental factors. For example, did you know that the age of the parents plays a role? Canadians are having children later in life, and studies show that children born to older parents are at higher risk of developing schizophrenia or psychosis.
Immigration is another factor mentioned by Dr. De Benedictis, as the children of immigrants often have a higher prevalence. Finally, there is our living environment. Rapid urbanization is not insignificant. We have known since the 1960s that living in the city is associated with more psychosis. For a long time, it was believed that this was a statistical bias—because there are more doctors in cities. Not so, say the two experts. Studies have shown that urban living is, in itself, a predisposing factor. With more and more Canadians crammed into cities and suburbs, this is a factor that can no longer be ignored.
According to the source: ici.radio-canada.ca
Created by humans, assisted by AI.