Tobacco and Cannabis Use by Teens Both Raise Psychosis Risk

Both heavy cigarette smoking and use of cannabis in adolescence are individually linked with an increased risk for psychosis, according to a pair of recently published studies.

The studies were based on groups of more than 6000 people from the Northern Finland Birth Cohort of 1986. At age 15-16, participants answered questions about alcohol and drug use and psychotic experiences. The young people were followed through age 30.

According to findings published online in Acta Psychiatrica Scandinavica, smoking 10 or more tobacco cigarettes a day was associated with a greater risk of psychosis, compared with not smoking. Smoking before age 13 also was linked with increased psychosis risk. The associations remained significant even after researchers adjusted for known psychosis risk factors including cannabis use, frequent alcohol use, previous psychotic experiences, and parental history of psychosis.
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“Based on the results, prevention of adolescent smoking is likely to have positive effects on the mental health of the population in later life,” said researcher and professor Jouko Miettunen, MD, PhD, University of Oulu, Finland.

In a study published online in The British Journal of Psychiatry, researchers reported teens who used cannabis 5 or more times had an elevated risk of psychosis that remained statistically significant after adjusting for prodromal symptoms, other substance use, and parental psychosis.

“Our findings are in line with current views of heavy cannabis use, particularly when begun at an early age, being linked to an increased risk of psychosis,” said Antti Mustonen, MD, University of Oulu. “Based on our results, it’s very important that we take notice of cannabis-using young people who report symptoms of psychosis. If possible, we should strive to prevent early-stage cannabis use.”

—Jolynn Tumolo

References

Mustonen A, Ahokas T, Nordström T, et al. Smokin` hot: adolescent smoking and the risk of psychosis. Acta Psychiatrica Scandinavica. 2018 February 18;[Epub ahead of print].

Mustonen A, Niemelä S, Nordström T, et al. Adolescent cannabis use, baseline prodromal symptoms and the risk of psychosis. The British Journal of Psychiatry. 2018 March 4;[Epub ahead of print].

Smoking heightens risk of psychoses [press release]. Helsinki, Finland: Academy of Finland; March 12, 2018.