Could Pot Use Speed Up The Onset Of Schizophrenia?

By Britni de la Cretaz 11/08/17

A new study examined the effect of marijuana use on the under-developed brains of adolescents.

person blowing out smoke in technicolor.

While most research into cannabis has focused on examining the potential benefits for people with chronic pain and other health issues, some scientists argue that more work needs to be done to examine what effect that consuming cannabis could have on the under-developed brains of adolescents. They are taking on that research, with somewhat concerning results.

On October 9, Hannelore Ehrenreich of the Max Planck Institute of Experimental Medicine presented the results of a study of 1,200 people with schizophrenia at the World Psychiatric Association’s World Congress in Berlin. That study has been submitted for publication, according to Scientific American.

The results show that those in the study group who had used marijuana before age 18 had an onset of schizophrenia approximately 10 years earlier than those who had not. Earliest onset was associated with the highest frequency of cannabis use in adolescence. The study also looked at genetics and alcohol use as risk factors, but neither were correlated with earlier onset.

Based on these findings, Ehrenreich concluded, “Cannabis use during puberty is a major risk factor for schizophrenia.” According to Scientific American, there have been other studies that corroborate Ehrenreich’s findings.

Robin Murray, a professor of psychiatry at King’s College London, is one of the first scientists who formally researched the connection between marijuana and schizophrenia. He spoke about the issue at the conference in Berlin, as well.

“There is no doubt” that cannabis use in adolescence increases the risk of developing schizophrenia as an adult, said Murray. According to Scientific American, Murray cited 10 other studies that showed similar findings.

Earlier this year, the National Academies of Sciences, Engineering, and Medicine released a report indicating that cannabis use "is likely to" increase the risk of developing schizophrenia and other psychoses.

However, not everyone is convinced. “The available data on this subject is far from definitive—particularly with regard to any potential cause-and-effect relationship,” Paul Armentano, deputy director of NORML, a U.S. organization that advocates marijuana legalization for adults, told Scientific American. “For instance, increased cannabis use by the public has not been followed by a proportional rise in diagnoses of schizophrenia or psychosis.”

According to the National Institute on Drug Abuse, marijuana is the most commonly used drug by teens in the United States. In 2016, almost half of teens reported marijuana use by their senior year of high school.

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Britni de la Cretaz is a freelance writer, baseball enthusiast, and recovered alcoholic living in Boston. Follow her on Twitter at @britnidlc.