According to the National Survey on Drug Use and Health (NSDUH), the most commonly used substance among teens is alcohol, followed by tobacco. The most commonly used illegal drug is marijuana. In 2015, 9.6 percent of 12 to 17 year-olds had used alcohol, 4.2 percent had used cigarettes, and 7.0 percent had used marijuana in the month prior to the survey.

You can learn more about drug use trends and statistics at: http://www.drugabuse.gov/related-topics/trends-statistics