The biennial High School Youth Risk Behavior Surveillance System survey from the Centers for Disease Control and Prevention revealed that the rate of marijuana use among U.S. high school students remained virtually unchanged from 2011 to 2013. It's also about 3 percent less than the peak of teen marijuana use in 1999, when nearly 27 percent of teens said they had recently used marijuana, according to the CDC data.

...The CDC's findings are similar to those in a recent report published in the Journal of Adolescent Health, which compared 20 years of CDC YRBS data about high school teens' marijuana habits in states that have legalized medical marijuana compared with neighboring states that continue to ban the plant. It found that legalization of marijuana for medical purposes did not result in greater illicit use of the substance by high school students.

“Rates of teen alcohol and cigarette use have dropped, and we didn’t have to arrest any adults for using them,” Tvert said. “We could see the same results by regulating marijuana. Regulation works.”

Data was available for Colorado from 2009 to 2011, during a period of rapid medical marijuana dispensary expansion in the state, which ballooned to around 500 shops statewide. That data showed Colorado high school students' marijuana use decreased by nearly 3 percent.