Cannabis may now cause one in four new cases of schizophrenia in men
This stunning figure - from a Danish researcher last week at a top international psychiatry conference - spells a mental health crisis and a crushing blow for advocates of cannabis legalization.
Like The New York Times, psychiatrists may finally be waking up to the imminent mental health disaster coming after decades of lies about the risks of cannabis to the brain.
Last week, at the 2022 International Congress of the Royal College of Psychiatrists, a Danish researcher suggested that cannabis might be responsible for 25 percent of new cases of schizophrenia in young men.
This figure is far higher than previous estimates, which generally ranged from 5 to 10 percent. It would translate into tens of thousands of additional cases of new-onset schizophrenia annually in the United States and Europe.
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To put a 25 percent figure in context, genetic factors are generally said to account for about half of the risk of schizophrenia. This estimate would imply that cannabis use now carries roughly half as much as risk overall as a genetic predisposition to the illness.
Schizophrenia is among the most serious mental illnesses, causing lifelong unemployment and disability in many patients and reducing their life expectancy by about 15 years on average. Untreated schizophrenia is also a high risk factor for extreme violence.
Carsten Hjorthøj, an associate professor at the University of Copenhagen and research leader at Copenhagen Research Center for Mental Health, presented the data. The International Congress is the annual conference of the Royal College of Psychiatrists, which oversees the practice of psychiatry in Great Britain.
Some American physicians are also, at last, acknowledging the problem. On Friday, Dr. Scott Hadland - the chief of adolescent and young adult medicine at Harvard Medical School - wrote that:
The true dimensions of the potential crisis are effectively impossible to know at this point, especially in the United States.
As I wrote in Tell Your Children, the United States does not even attempt to count the number of Americans with schizophrenia, much less count new schizophrenia diagnoses annual or track changes in them. But data from countries such as Denmark and Scotland suggest a worsening surge in hospitalizations for cannabis-linked psychosis and schizophrenia.
The mental-health care system is simply not set up to handle a large increase in new cases of schizophrenia. Treating people who have just had their first psychotic break is complex, stressful, and expensive, and after 50 years of deinstitutionalization, American psychiatric hospitals are near-full at the best of times.
In other words, if cannabis really is provoking a notable increase in new schizophrenia cases, the strain on the system will be hard to hide. The question will be whether legalization advocates and for-profit cannabis companies can succeed following the Big Tobacco strategy and hiding their culpability.