Study: Marijuana Can Affect Teen Brains, No Matter the Amount

The study shows evidence of structural brain and cognitive effects with just one or two instances of cannabis use in adolescence.
Published: January 16, 2019

A recent study found that teenagers who used recreational marijuana as little as one or two times could see changes in their brain.

The study, which was published Monday in the Journal of Neuroscience, looked at 46 14-year-olds who showed increased volume on MRI scans in parts of the brain involved in emotion-related processing, learning and forming opinions.

Hugh Garavan, the lead author of the study, says he and his team were curious to investigate the popular assumption that one or two joints would have no impact, reports NBC News.

“We were curious to study this and especially to investigate if first uses may actually produce brain changes that affect future behavior like subsequent use,” he said.

——Article Continues Below——

Get the latest industry news and research delivered directly to your inbox.

Garavan is a professor of psychiatry and the University of Vermont School of Medicine.

Researchers believe that the enlargement of gray matter seen in the brain scans of the teens suggests a disruption in normal adolescent development.

“One possibility is that the cannabis use has disrupted this pruning process, resulting in larger volumes (i.e., disruption of typical maturation) in the cannabis users,” Garavan said. “Another possibility is that the cannabis use has led to a growth in neurons and in the connections between them.”

According to the most recent data from the National Institute of Drug Abuse, 32.6 percent of tenth graders reported using marijuana at least once during their lifetime.

The institute says risks of marijuana use include reduced school performance, reduced life satisfaction, impaired driving and use of other drugs.

These studies come at a time where marijuana is now legal in 10 states and more are expected to follow.

Teens are also using e-cigarette products to smoke marijuana, according to this study. Students who participated reported using e-cigarettes to vaporize hash oil, marijuana leaves and wax infused with THC.

E-cigarettes have been the most commonly used tobacco product among middle and high school students since 2014, according to the CDC. Recent data showed there was a 78 percent increase in youth vaping between 2017 and 2018.

The FDA has cracked down on e-cigarette companies like Juul and is considering banning flavored products form the market, as they can be more appealing to teens.

According to another study published on Monday medical journal Pediatrics, teens who live in areas with strong regulations could be at lower risk of tobacco use, reports CNN.

“We found that youth living in areas with strong licensing requirements were less likely to begin using e-cigarettes and cigarettes during the one-and-a-half-year follow-up, on average, compared to youth who resided in areas with weaker regulations,” said Rober Urman, an author of the study.

Researchers say more work is needed to find solid evidence about the enlargement of gray matter and the negative effects on the brain.

Garavan and his team plan to investigate the effects of alcohol and other psychoactive substances as well.

Strategy & Planning Series
Strategy & Planning Series
Strategy & Planning Series
Strategy & Planning Series
Strategy & Planning Series