A new study has revealed that teens are using e-cigarettes to vaporize nicotine and marijuana. The study, which included about 4,000 Connecticut teens, found that about 20% of the participants accepted that they used the device to smoke nicotine and pot.

The study researchers said they have found the first evidence which showed that high school students are using e-cigarettes to vaporize marijuana. The study published in the journal Pediatrics warned that the increasing use of e-cigarettes can boost more US teens to use the device to smoke cannabis. It could expose the high school students to higher concentrations of tetrahydrocannabinol.

An earlier study suggested that teens who try the device could soon move to conventional cigarette smoking. The United States Centers for Disease Control and Prevention (CDC) revealed that about 2 million US teens last year tried e-cigarettes. According to the CDC, the figures are surprising as they are triple the number of teen users in 2013.

Meghan Morean of Oberlin College in Ohio and other researchers said 18% of teens reported to use e-cigarettes to smoke cannabis in some form. The study revealed that male teen students have been found using e-cigarettes to smoke cannabis than female students.

Dustin Lee, a postdoctoral fellow at the Geisel School of Medicine at Dartmouth College in New Hampshire, said the study’s results are worrisome. “We know very little about the acute and long-term effects of high-potency THC on neurobiology and behavior. This is especially concerning for teens who are in a critical time for development of brain structures that are integral in executive functioning”, Lee added.