"Clearly our public health prevention efforts, as well as policy changes to reduce availability, are working to reduce teen drug use, especially among eighth graders," Dr. Nora Volkow, director of the National Institute on Drug Abuse, said in a statement accompanying the study results. "However, when 6 percent of high school seniors are using marijuana daily, and new synthetics are continually flooding the illegal marketplace, we cannot be complacent," Volkow said. According to the study, marijuana and e-cigarettes are more popular among teens than regular tobacco, with a large drop in the use of tobacco cigarettes among 8th, 10th and 12th graders.