Schizophrenia Genes Worsen Effects of Early Cannabis Use

Cannabis use during early adolescence may accelerate the decrease in cortical thickness in males at genetic risk for schizophrenia, new research suggests.

Decreased thickness of the cortex during male adolescence is part of normal maturation, study author Tomáš Paus, MD, PhD, Tanenbaum Chair in Population Neuroscience, senior scientist, the Rotman Research Institute, and professor of psychology and psychiatry, University of Toronto, in Canada, told Medscape Medical News.

“But it looks like in those boys who have both tried cannabis before age 16 and have a higher risk score for schizophrenia, the thinning is accelerated, the decrease seems to be steeper.”

The research is published in the October issue of JAMA Psychiatry.

Male Brain More Vulnerable?

Dr Paus stressed the importance of putting the study in context.

Cannabis use before age 16 years, he said, is very common ― about 30% of children in Canada try cannabis before they turn 16 ― and early use is strongly linked to the later development of schizophrenia.

Also, it is well known that schizophrenia begins about 5 years earlier in males than females and that the male brain differs from the female brain during adolescence.

“From images of typically developing kids, hundreds and thousands of them now, we know that during male adolescence, there is more restructuring of the brain compared with girls,” possibly owing to the influence of sex hormones. This, said Dr Paus, might make the male brain more vulnerable to insults during this period.

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They should really include this warning of any medical dispensary of marijuana in Canada or elsewhere where they sell it.

Eh, yeah. Our incoming PM is a doofus pothead. Good luck with that.


I started at ~17. I think a few months before I turned 17, not sure. I’m assuming this is just another completely correlational study though. And also not a logitudinal/cohort study. Is it? When I click the link it just tells me to log in.

pretty ironic they are prescribing it now in certain states in America,

so i guess they wont be using it for ADHD any time soon then lol

btw how did they do the study? do they look at brain scans or what? it would be cool to map the brain like that

i think if they mapped my brain while on meds and after there would be two different patterns, two different networks, i think i have two for the price of one in here lol,