TORONTO – Certain genes that put you at risk of developing schizophrenia may also be at play in increasing your odds of smoking weed, a new study suggests.
Handfuls of previous research already link marijuana use to schizophrenia, but scientists haven’t been able to explain why. Now, British researchers out of King’s College London suggest that it boils down to genetics that make some vulnerable to both.
“We wanted to explore whether this is because of a direct cause and effect or whether there may be shared genes which predispose individuals to both cannabis use and schizophrenia,” lead researcher Robert Power said in a university statement.
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This is the first time scientists have pointed to genes as the culprit that connects schizophrenia to smoking pot, British reports say.
The researchers studied nearly 8,100 healthy people – half of which smoked weed. Each participant’s ‘genetic risk profile’ was pulled so the doctors could count out how many genes were related to schizophrenia.

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Turns out, those who appeared to be genetically predisposed to the disorder tended to use marijuana more. They also relied on the drug in greater quantities.
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Schizophrenia affects about one in 100 people and people who use cannabis are twice as likely to develop the disorder, Power said.
Schizophrenia is marked by delusions, hallucinating, and hearing voices. Power said doctors acknowledge that getting high can increase the risk of this condition, too.
“We know that cannabis use increases the risk of schizophrenia. Our study certainly doesn’t rule this out, but it suggests there is likely to be an association in the other direction as well – that predisposition to schizophrenia also increases your likelihood of cannabis use,” he said.
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In Canada, schizophrenia affects about one per cent of the population, according to the national Mental Health Association.
Ultimately, Power said he hopes his findings shed light on the relationship between genetics and our environment. Certain risks, such as marijuana, may be within reach for those who are most vulnerable based on their genetics, he said.
“This is an important finding to consider when calculating the economic and health impact of cannabis,” he concluded.
Power’s full findings were published Tuesday in the journal Molecular Psychiatry.
carmen.chai@globalnews.ca
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