With many states successfully passing marijuana legislation, nationwide legalization seems closer than ever. Now, a recent study by the University of Michigan may help alleviate concerns that legalization for adults could lead to increased teen cannabis use.

While the data shows that older adults might be more likely to try marijuana upon legalization, the increased use did not apply to teenagers. The findings echoed the results of previous studies.

“There has been no policy influence on cannabis incidence in the underage adolescent population after adults have been allowed to buy cannabis in retail shops,” the study’s authors wrote in a peer-reviewed research article published in the journal PLOS One. “Legalized cannabis retail sales might be followed by the increased occurrence of cannabis onsets for older adults, but not for underage persons who cannot buy cannabis products in a retail outlet.”

Study Focuses on First-Time Use

While previous studies on this topic have focused on the impact of legalization on frequency of marijuana use and consumption levels, this new study instead focused on whether legalization impacts if and when people consume cannabis for the first time.

The study, partially funded by the National Institutes of Health, examined current research on teen alcohol use in the U.S. that showed a majority of American young adults do not start consuming alcohol until they are legally of age. The researchers created the hypothesis that marijuana consumption could follow the same pattern.

Barrett Wallace Montgomery, the lead author of the study, told Marijuana Moment that the inspiration behind the study was people implying that others would use marijuana either way, regardless of legality. He did not think it was a given.

The study focused on people ages 12 to 20 years old who cannot legally purchase marijuana in any state. While the results did show minor ups and downs in teen cannabis use, researchers expect those deviations over time, unrelated to legalization.

More Adults Try Marijuana With Legalization

In contrast, legalization had a clear impact on people over 21 choosing to legally try cannabis for the first time. The study shows up to a 1.3% increase in adult marijuana use after legalization. This may not seem like much, but it means adults trying marijuana for the first time could double or even triple after legalization.

The study used public data from more than 800,000 people ages 12 years old and older who participated in the National Survey on Drug Use and Health. Researchers put the participants into two groups, the first consisting of ages 12-20 and the second consisting of adults 21 years old and older.

This isn’t the first study to determine that legalization doesn’t show an increased use of cannabis in underaged individuals. The Journal of the American Medical Association published a report in September 2021 that demonstrated the impact of legalization on teenage marijuana use is “statistically indistinguishable from zero.”

Studies like this help quell fears of lawmakers who are concerned with teen marijuana use increasing if marijuana is legalized.