Teen marijuana use has declined over the past decade, but new research shows that girls are now using it more than boys.

A recent study by researchers at Florida Atlantic University, published in Pediatric Reportsshows that despite fears that state-level marijuana legalization in the US could lead to increased use among teenagers, use is actually declining. However, the study also notes that girls now outnumber boys in using marijuana.

The study examines trends in marijuana use among US adolescents from 2011 to 2021, using data from the Youth Risk Behavior Survey of high school students in grades 9-12.

What the study reveals

Overall, it included a total sample of 88,183 US high school students who provided self-reports of their marijuana use.

During this time, reported marijuana use among teenagers has shown a significant decline.

The proportion of teens who had ever tried marijuana fell from 39.9% in 2011 to 27.8% in 2021, and the percentage of college students who reported using marijuana in the past 30 days fell from 23.1% to 15 .8%.

There was also a reduction in the percentage of students who first used marijuana before the age of 13.

These declines show that fewer teens are using marijuana, which is a positive development, the study’s authors say, given the problems associated with marijuana use during this developmental period.

The study found that trends in marijuana use vary by demographics such as race, class level, and gender.

Among racial groups, black adolescents reported the highest marijuana use, while Asian adolescents reported the lowest use.

“This finding aligns with previous research indicating that minority groups, particularly black adolescents, may perceive lower risks associated with marijuana use, which may contribute to higher rates of use,” the study said.

The rate of marijuana use increased with each grade level, reaching the highest rate among twelfth graders.

“Although we found a net decrease in the percentage of students using marijuana between 2011 and 2021 for all grade levels, there was consistently higher use for older grades across all years, particularly among students in twelfth grade”, note the authors.

The most notable trend is that by 2021, girls were more likely than boys to use marijuana, reversing the previous trend in 2011, when boys were more frequent users.

“This change is consistent with previous reports suggesting a narrowing of the gender gap in substance use,” the study says. Researchers believe the increase in marijuana use among girls could be attributed to evolving social dynamics, including more integrated friend groups where girls may have greater exposure to marijuana offers from male peers.

The researchers noted that despite the overall decline in marijuana use among teens, certain groups — particularly older teens and teens of color — continue to have relatively high rates of use.

Therefore, they suggest that culturally tailored interventions, along with prevention in schools and families, can maintain this decline and address specific disparities between these groups.

Specifically, the authors of this study emphasized that continued public health efforts are needed to reduce marijuana use among adolescents, especially now that marijuana is becoming more accepted through its legalization. For researchers, greater availability could mean teens will have greater access to marijuana and may accept perceptions of its safety.

Limitations of this study

As the author of this research notes, their findings have some limitations.

First, it relies on self-report and may introduce biases such as social desirability and recall errors that could decrease the accuracy of reported marijuana use. In addition, the cross-sectional design of the study will not allow causality to be inferred from observed trends and contributing factors.

The study also does not include information on critical contextual details, such as the frequency and potency of marijuana use, nor does it account for variations in state marijuana legalization that may differentially influence adolescent behaviors in different regions.

Although the sample is nationally representative at this level, the experiences of adolescents not in traditional school settings may not generalize.

Finally, this study does not account for other confounding influences such as socioeconomic status and peer effects, an indication that research on adolescent marijuana use should be conducted using longitudinal studies to understand their tendencies.

Trends in adolescent marijuana use

This study reflects a trend where, despite declining use over the past 10 years, marijuana remains popular among teenagers.

This also appears to be true among young adults, as confirmed by a Gallup Report 2022 which found that teenagers are less interested in cigarettes, opting instead for vaping or marijuana. Cigarette smoking among young adults has fallen from 35% to 12% over the past two decades, while marijuana use has doubled, with 26% reporting use between 2019 and 2022, up from 17% in 2013-2015.

Marijuana vaping among teenagers has also increased. A 2021 study disclosure that lifetime use doubled from 6.1% between 2013 and 2016 to 13.6% between 2019 and 2020. In that study, researchers attributed this increase to easy access to vaping devices, enticing flavors and social media promotion.

Finally, teens are also turning to less regulated alternatives to marijuana, such as delta-8 THC productswith a recent study showing that 11.4% of high school students reported using them in the past year.