A national survey of more than 2,000 high school seniors across the country found that more than 11% used a drug called delta-8 THC in the past year.

The psychoactive compound is derived from hemp, and often called "diet weed' or "weed lite." It's milder than its cousin, delta-9 THC, the main intoxicant in marijuana, but has similar effects on the brain and the body.

The percentage of teens using the drug is higher in the 19 states with no regulations around the compound and in states where marijuana has not been legalized.

The findings are published in a study published this week in JAMA. The data comes from Monitoring the Future, which surveys teen behaviors. It's the first time teens were asked about this drug in this survey.

"It's a growing concern," says Renee Johnson, a professor at Johns Hopkins School of Public Health. Johnson wasn't involved in the new study, but wrote an accompanying editorial about the public health concerns over the largely unregulated sale of delta-8 THC products.

Products containing delta-8 began to be marketed after the 2018 Agricultural Improvement Act (commonly known as the Farm Bill) included a provision legalizing the sale of hemp-derived cannabis products, containing less than 0.3% of delta-9 THC. This led to the "de facto legalization" of hemp-derived psychoactive delta-8 products," writes Johnson.

But the problem is the lack of oversight around delta-8 products – often sold as edibles or vapes – in many states, says Johnson.

"What is sold is unregulated," she says. "In most states we don't know the potency [of the drug]."

Delta-8 products are made by processing hemp-derived CBD, which can concentrate the drug, she adds. "We're getting higher concentrations of it than we would have ever got in an actual cannabis plant."

Preliminary studies show users reporting adverse health effects, including "cough, rapid heart rate, paranoia, anxiety, breathing problems and seizure," says Johnson.

And teens in particular are at greater risk of these symptoms. "They're new to drugs. So they're not great at taking drugs and understanding how long it takes to feel the effects, when to stop all of that," says Johnson.

Johnson is particularly concerned about teens consuming edibles containing delta-8 THC.

"Most people probably don't have a good sense of how long it takes for an edible to hit," she explains. "So it takes 30 to 40 minutes. So they could wait 20 minutes. Beyond that, they take another and then they've sort of over ingested."

That brings a "real risk of folks going to the hospital for over-ingestion of cannabis."

Most states also don't have laws requiring labeling of products containing delta-8, she adds. "When there is labeling, studies show that the labels are wrong. There are no standards for how this stuff is manufactured."

Public health officials have taken note of the risks of the drug. In 2022, the Food and Drug Administration issued a warning about the potential risks, stressing that the agency has not evaluated or approved the delta-8 THC for safe use. It noted that poison control centers received more than 2,300 delta-8 exposure cases between January 1, 2021, and February 28, 2022.

As of January 2023, delta-8 had been banned in 15 states and is regulated in some way in eight others, according to Johnson's editorial.

Copyright 2024 NPR. To see more, visit https://www.npr.org.