MONDAY, Feb. 13, 2023 (HealthDay News) -- It’s not clear why, but youths in U.S. states where medical marijuana is legal report more vaping of cannabis than their peers in states where weed is legal for all adults or it is completely illegal.

New research found that about 27% of 12th graders in medical marijuana states reported vaping cannabis compared to 19% in states that bar the drug or allow it for adult use.

“More than a quarter of our youth in medical states were vaping cannabis. That's a lot,” said first author Christian Maynard, a doctoral student in sociology at Washington State University.

“We were expecting medical and adult use states would be more similar. Instead, we didn’t find any statistical difference between prohibited and adult use states," he said in a university news release.

For the study, Maynard and his university adviser, sociologist Jennifer Schwartz, analyzed responses from 3,770 high school seniors in the 2020 Monitoring the Future survey. It has surveyed U.S. youth since 1975.

They also analyzed a subset of 556 participants who had answered questions about access to cannabis vaping products and perceived risks. In all, 62% of high school seniors in states where just medical marijuana was legal reported very easy access to cannabis vaping cartridges. Just 31% saw regular cannabis use as a great risk.

About 52% of high school seniors said they had easy access to cartridges in states where marijuana was prohibited and where it was allowed for adult recreational use.

More teens also considered regular cannabis use risky -- about 40% in prohibited states and 36% in adult-use states.

Maynard offered some potential reasons.

“It’s possible the context of saying cannabis is for medical reasons is contributing to the fact that youth view it as less risky,” he said. “The difference in availability may also be that adult-use states are providing legal cannabis to a wider range of people, which may in turn tamp down on the illegal market, and an adolescent can't go to a dispensary.”

Maynard said more research on this is needed.

Cannabis and tobacco use among teens has been decreasing overall. But cannabis vaping during the past month made the second-biggest single-year jump in 2019 for any substance in the study’s 45 years, researchers noted. It came in second to nicotine vaping.

Despite lung injuries that led to more than 2,000 hospitalizations and 68 deaths in 2019 and 2020, vaping continues to be popular, the study noted. Many of the injury cases were connected to cartridges containing vitamin E that are sold outside stores, according to the U.S. Centers for Disease Control and Prevention.

Parents and educators need to help inform kids of the dangers, Maynard said.

“Like it or not, cannabis legalization seems to be happening across the country,” he said. “It's very important to talk with adolescents. We know that at a younger age when the brain is developing that cannabis is associated with harmful side effects. It’s also not safe to buy cannabis carts off the streets. You don’t know what they're putting in those unregulated carts.”

The findings appear in the March issue of the journal Drug and Alcohol Dependence Reports.

More information

The U.S. Centers for Disease Control and Prevention has more on the risks of vaping.

SOURCE: Washington State University, news release, Feb. 9, 2023