A new study shows that vaping THC may be worse for teens than smoking weed or cigarettes, or vaping nicotine.

The University of Michigan’s findings indicate when vaping cannabis, adolescents aged 12 to 17 have a greater chance of lung injury symptoms like developing a dry cough or wheezing, which can hinder sleep, speech, or exercise. According to Carol Boyd, co-director of the University of Michigan’s Center for the Study of Drugs, Alcohol, Smoking and Health, it’s unclear how long such symptoms could last.

“We found, and it was something that surprised us a bit, that it was the lifetime vaping cannabis that was associated with a far greater number of symptoms and a higher likelihood of having each of these symptoms than using either e-cigarettes or cigarettes,” Boyd said, per U.S. News. In this case, “lifetime” refers to any past use.

The data disputes popular thinking that smoking cigarettes or vaping nicotine is worse for your lungs.

“I think that industry would probably like to show that vaping e-cigarettes is healthier, that it’s the cannabis vaping causing these respiratory symptoms, not the e-cigarettes. This is not true. E-cigarette vaping also causes symptoms among youth,” Boyd said. “However, in our study, and when we took into account their e-cigarette use, we found higher odds of having these respiratory symptoms among youth who had vaped cannabis.”

Vaping cannabis has become more popular over the last few years and was linked to a string of lung illnesses and deaths prior to the COVID-19 pandemic. The CDC discovered that the culprit was tied to vitamin E acetate, which “has been used as a cutting agent in e-liquids containing THC,” Bloomberg writes.