Cannabis & Psychosis: Exploring the Link

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Cannabis & Psychosis: Exploring the Link

Cannabis May Influence Onset of Psychosis

An article posted on February 7th by Scientific American:

Research to be published this summer finds that the use of cannabis is associated with the early onset of psychosis.

By Christie Nicholson

Pot is one of those drugs that appears to maintain a fairly good rep, despite its growing bad rep. Consider this research that will be published this June in the Archives of General Psychiatry.

This particular study found that marijuana use is associated with early development of psychosis. Scientists analyzed 83 studies involving over 8,000 subjects who used pot and over 14,000 subjects who did not. They compared the age of onset for psychosis between these groups. And they found that those who used cannabis developed psychosis nearly three years younger than those who did not use any pot.

The researchers proposed some theories behind the pattern. One that cannabis use is a causal factor for schizophrenia, or that it precipitates psychosis in vulnerable people. They also theorize that cannabis might simply exacerbate symptoms of schizophrenia. Or the link could come from the other direction of course, those suffering from schizophrenia may be more likely to use pot.

The evidence here suggests that limiting marijuana use could delay or even prevent some cases of psychosis. And timing is important, since earlier onset of schizophrenia is linked to a worse prognosis overall.


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Cannabis Use and Earlier Onset of Psychosis

Cannibis smokers have a seven-fold schizophrenia risk

Harper government devotes funds to studying the link between marijuana use and mental illness

An article published in yesterday's edition of The Toronto Star:

WINNIPEG – The Harper government is putting up $550,000 to gather research on marijuana use and mental illness.

The Schizophrenia Society of Canada will use the money to further research the links between cannabis and early psychosis as well as develop promotional materials warning youth about the dangers of smoking pot.

The money is part of Ottawa's $30 million national anti-drug strategy announced in 2007.

Chris Summerville, CEO of the Schizophrenia Society, said the public doesn't realize that cannabis users have a seven-fold increase in risk of developing schizophrenia.

He pointed to recent research out of Victoria, B.C., linking pot smoking and mental illness.

As part of the society's research, some 30 youths who have experienced psychosis will be trained to gather information about the reasons their peers use cannabis.

The results will be used to develop educational materials aimed at decreasing the use of illicit drugs among young people.

Winnipeg Conservative MP Joy Smith said Tuesday that while the public regards marijuana as a soft drug, there may be very serious consequences for young pot smokers who have a predisposition to mental illness.

"Science has shown that cannabis may actually trigger the onset of psychosis and may also intensify the symptoms for those who already have a psychotic illness," Smith said in announcing the grant.

"It has been suggested that up to 80 per cent of youth who have had a psychotic episode were using cannabis. And that's pretty shocking," said Smith, who was filling in for Health Minister Leona Aglukkaq at news conference.

Photograph by Rotbuche.