"Concerns about laws and policy measures that may inadvertently affect youth drug use merit careful consideration. Our study does not show evidence of a clear relationship between legalization of marijuana for medical purposes and youth drug use for any age group, which may provide some reassurance to policymakers who wish to balance compassion for individuals who have been unable to find relief from conventional medical therapies with the safety and well-being of youth. Further research is required to track the trends in marijuana use among adolescents, particularly with respect to different types of marijuana laws and implementation of laws in each state."
Choo, Esther K. et al. (2014), "The Impact of State Medical Marijuana Legislation on Adolescent Marijuana Use," Journal of Adolescent Health, Volume 55, Issue 2, p. 160 - 166.