FRIDAY, April 25, 2014 (HealthDay News) -- American teens' use of marijuana doesn't increase when states approve the drug for medical use, a new study finds.
"Any time a state considers legalizing medical marijuana, there are concerns from the public about an increase in drug use among teens," principal investigator Dr. Esther Choo, an attending physician in the department of emergency medicine at Rhode Island Hospital, said in a hospital news release.
Choo's team examined 20 years of data from states that do and don't permit medical marijuana use. They found that legalizing medical marijuana did not lead to increased illicit pot use by high school students.
The data showed that nearly 21 percent of teens had used marijuana in the past month, but there were no significant differences in pot use before and after a state legalized medical marijuana, according to the study released online April 15 in advance of print publication in the Journal of Adolescent Health.
She said the findings add "to a growing body of literature published over the past three years that is remarkably consistent in demonstrating that state medical marijuana policies do not have a downstream effect on adolescent drug use, as we feared they might."
Medical marijuana is currently legal in 21 states and the District of Columbia.
"Researchers should continue to monitor and measure marijuana use," Choo said. "But we hope that this information will provide some level of reassurance to policymakers, physicians, and parents about medical marijuana laws."
The U.S. National Institute on Drug Abuse has more on the medical use of marijuana.