Marijuana Use Prevalence and Trends Among Youth in the US

"During the 1990s, the annual prevalence of marijuana use tripled among 8th graders (from 6% in 1991 to 18% in 1996), more than doubled among 10th graders (from 15% in 1992 to 35% in 1997), and nearly doubled among 12th graders (from 22% in 1992 to 39% in 1997). Among college students, however, the increase in marijuana use, presumably due to a generational replacement effect, was much more gradual. Annual prevalence of use rose by about one third, from 27% in 1991 to 36% in 1998. Marijuana use began to decline in 1997 among 8th graders and then did the same in 1998 among 10th and 12th graders. The rate of decline was rather modest, however, perhaps due in part to effects of the public debates over medical use of marijuana during that period. In 2001, use remained level in all three grades, but between 2001 and 2004 all three grades showed significant declines in their annual prevalence of marijuana use, with the proportional decline greatest among 8th graders. Eighth graders exhibited the steadiest long-term decline from their recent peak in 1996, a decline of more than four-tenths by 2007. After 2007 use began to increase among 8th graders (see Figure 5-4a in Chapter 5). Declines among 10th and 12th graders started a year later and accelerated after about 2001; between approximately 1997 and 2008, annual prevalence levels fell by 31% and 18% for 10th and 12th graders, respectively. All three grades exhibited slight increases in annual prevalence after the mid-2000s, although the increases were uneven. From 2014 to 2015 levels of use did not significantly change among secondary school students, while among the older samples annual prevalence of marijuana increased, by 2.4 points (s) to 34% among young adults and by 3.5 points (ns) to 38% among college students. This increase specific to the older age group may represent a cohort effect – a continuation of the higher levels of marijuana use in this cohort that was first observed when it was younger in 2008-2011 – and/or the recent publicity and debates about recreational marijuana use may have had more effect on the marijuana attitudes and behaviors of the older groups."


Miech, R. A., Johnston, L. D., O’Malley, P. M., Bachman, J. G., & Schulenberg, J. E. (2016). Monitoring the Future national survey results on drug use, 1975–2015: Volume I, Secondary school students. Ann Arbor: Institute for Social Research, The University of Michigan, pp. 13-14. Available at