The effects of cannabis, however, may be the most pronounced in those who are at the greatest risk for psychosis or addiction. However, brain volumes did not differ between siblings discordant for cannabis exposure, according to the study. The findings were published online on August 26 in the journal JAMA Psychiatry by an global team of researchers.
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“That means there could be widespread elements, genetic and environmental, that predispose us to utilizing marijuana that additionally contribute to variations in our mind volumes”, Agrawal advised Reside Science. The results indicate that cannabis might have some effect on the developing brains of at-risk male teenagers, the researchers conclude.
The investigators found that among the three groups, a negative association was observed between cannabis use in early teens and cortical thickness in male participants with a high polygenic risk score, meaning that cannabis use was associated with a thinner brain cortex in these teens. But we still don’t know everything about it. The studies suggest that a person’s environment, culture and genes all play murky roles in the process.
In general, the results are useful for researchers, but most people should not be concerned by them, he said. Instead they found that both exposed and unexposed siblings had the same volume.
He said: ‘Their brains showed lower cortical thicknesss compared with low-risk male participants and low-or-high risk female participants who used the drug’. As to establishing direct causality, Paus says there is still more research to be done.
The finding is consistent with the theory that early onset cannabis use may potentially exacerbate symptoms in a minority of subjects predisposed to the disease, but it contradicts claims that marijuana exposure is a likely cause of schizophrenia, particularly among those who are not already vulnerable to the disease.
In an editorial accompanying the new studies in the journal, Dr. David Goldman, a neurogeneticist at the National Institute on Alcohol Abuse and Alcoholism in Rockville, Maryland, wrote that the effects of marijuana may vary among people. But that research has the same chicken-and-egg problem as previous studies: The work can’t say whether pot causes those risks to increase, or whether people are more likely to smoke pot as their risk increases.
Pagliaccio and co-authors note that even though this is the largest study to examine the causal effects of smoking marijuana, there are still groups that weren’t included in the study that would be important to analyze.
The study’s senior author, Professor Tomas Paus, of Toronto University in Canada, said there was solid epidemiological evidence – that which looks at patterns across populations – supporting a link between experimenting with cannabis during adolescence and schizophrenia. “It is possible that any effects of marijuana may not have been detected because the sample may not be heavy users…”
The staff discovered that – even as soon as – did have smaller mind quantity within the amygdala, a area related to emotion processing and reward in search of, in contrast with those that had not smoked pot. “All we’re saying is that in the event you mix use with the genetic danger, then the mind is maturing in a barely totally different approach”, Paus advised Reside Science.
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A better understanding of whether or not marijuana has a significant impact on the brain is incredibly important as states around the country continue to discuss legalization of the drug.
