While there were slight decreases in the use of cocaine and methamphetamine among youth, teen marijuana use showed no signs of slowing down. In fact, according to the 2009 Monitoring the Future Survey, marijuana use among adolescents has increased gradually over the past two years after years of declining use; and past year rates of Vicodin and OxyContin abuse increased during the last 5 years among 10th graders and remained unchanged among 8th and 12th graders. The MTF Survey, which surveys youth in 8th, 10th and 12th graders, was released Monday by the National Institute on Drug Abuse (NIDA) and the University of Michigan.