Questions on the impact of medical marijuana laws on teenagers' illicit use of the drug have been raised repeatedly by public health officials. One study suggests that allowing marijuana to be sold for medical purposes doesn't harm teens.
Researchers compared teens in Rhode Island, where medical marijuana was legalized in 2006, with adolescents in Massachusetts, which doesn't allow medical marijuana sales. The analysis included 32,570 teens who completed surveys on drug use between 1997 and 2009. The study showed no statistically significant differences regarding marijuana use between the two states in any year.