Smoking Pot Doubles Mental Illness Risk

Tue Mar 1, 2005 - 12:15 pm EST

CHRISTCHURCH, New Zealand, March 1, 2005 ( – New Zealand researchers have established that marijuana use doubles the risk of developing a mental illness like schizophrenia. 

After interviewing 1,000 people about their history of cannabis use, the University of Otago researchers established that psychotic symptoms were more prevalent in cannabis users. They established that the relation between mental illness rates and drug use was not due to an underlying illness driving the users to use more marijuana. 

Lead researcher Professor David Fergusson said the increased psychosis risk resulted from chemical changes in the brain induced by marijuana. “Even when all factors were taken into account, there was a clear increase in rates of psychotic symptoms after the start of regular use,” he wrote in the journal Addiction, according to a BBC report. 

“These findings add to the growing body of evidence from different sources, all of which suggest that heavy use of cannabis may lead to increased risk of psychotic symptoms and disease in susceptible individuals.” 

UK mental health charity Rethink spokesman Paul Corry told the BBC news: “This is the latest in long line of international research over the last 12 months that shows we are facing a drug-induced mental health crisis.” 

Meanwhile, Canadian Marijuana Party leader Marc-Boris St-Maurice said Monday that he is joining the Liberal party, because he feels it is the best chance for legalization. “I think there is wide support for marijuana reform within the Liberal party,” St-Maurice said in a press release Monday. He plans to attend the Liberal Part convention this weekend to drum up support. 


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