Nearly one quarter of teens are using marijuana, according to a new survey.
Of eighth, 10th and 12th graders surveyed, 24 percent said they've used the drug in the past year, according to research from the University of Michigan. The 1.3 percent increase is the first significant rise in seven years.
The increase in teens using marijuana comes as more states legalize pot for medical and recreational use.
This year, 14.1 percent of high school seniors said they see "great risk" in smoking marijuana occasionally, down from 17.1 percent last year. Also, 64.7 percent said they disapprove of using the drug regularly, down from 68.5 percent last year.
Those statistics indicate marijuana use among teens could continue to grow, the study's principal investigator Richard Miech said.
"It should raise eyebrows," Miech said. "And people should be alert to the possibility that marijuana is about to launch."
Marijuana's popularity has flipped with cigarettes', the survey found. The percent of seniors smoking cigarettes daily has plummeted to 4.2 percent from 24.7 percent at its peak in 1997. Meanwhile, marijuana use has increased to 5.9 percent from its lowest point in 1992.
Vaping has become a popular mechanism for using marijuana and nicotine. Within the past year, 1 in 10 high school seniors reported vaping marijuana, and 19 percent of them said they vaped nicotine, according to the survey.