"Marijuana is one drug that is affected by some very specific policies, including medicalization and legalization of recreational use by adults. The effects on youth behaviors and attitudes of recent changes in a number of states will need to be carefully monitored in future years. Currently, marijuana does not hold the same appeal for youth as it did in the past, and today’s annual prevalance among 12th graders of 36% is considerably lower than rates exceeding 50% in the 1970s (documented by this project). However, if states that legalize recreational marijuana allow marijuana advertising and marketing, then prevalence could rebound and approach or even surpass past levels."
Johnston, L. D., O’Malley, P. M., Miech, R. A., Bachman, J. G., & Schulenberg, J. E. (2014). Monitoring the Future national results on drug use: 1975-2013: Overview, Key Findings on Adolescent Drug Use. Ann Arbor: Institute for Social Research, The University of Michigan.