Mitch Earleywine, PhD, Associate Professor of Psychology at the State University of New York at Albany, and Karen O’Keefe, JD, Attorney and Legislative Analyst for the Marijuana Policy Project, stated in their Sep. 2005 report "Marijuana Use by Young People: The Impact Of State Medical Marijuana Laws":

“Nine years after the passage of the nation’s first state medical marijuana law, California’s Prop. 215, a considerable body of data shows that no state with a medical marijuana law has experienced an increase in youth marijuana use since their law’s enactment. All have reported overall decreases of more than the national average decreases — exceeding 50% in some age groups — strongly suggesting that enactment of state medical marijuana laws does not increase teen marijuana use….

When states consider proposals to allow the medical use of marijuana under state law, the concern often arises that such laws might ‘send the wrong message’ and therefore cause an increase in marijuana use among young people.

The available evidence strongly suggests that this hypothesis is incorrect and that enactment of state medical marijuana laws has not increased adolescent marijuana use.”

Sep. 2005 - 2005 Teen Use Report