Nearly 90 percent of American teenagers say they know classmates who drink, smoke or use drugs, and many are doing it at school.
Columbia University released the survey Wednesday morning. The survey found that 44 percent of high schoolers know a student who sells drugs at their school.
Fifty-two percent of high school students say they know of places on or near school grounds where students go to get high during the school day.
This survey also found that social media played a big role in drug and alcohol use.