"• In 2018 the proportion of 12th graders who favor legalization of marijuana was 48%, about the same as the record of 49% set in the previous year. Support for legalization has been steadily and rapidly increasing since 2008, when it was near 30%. Prior to 2008, support followed a U-shape curve, in which support levels near 30% were present at the beginning of the survey, in 1975, then dipped by half to a nadir of 15% in 1986-88, only to redouble and return to around 30% by 1995, where it hovered for a decade before rising considerably.

"• The proportion of 12th grade students who favor treating marijuana use as a crime is at the lowest level ever recorded by the survey (11%), and its trend is a mirror image of the pattern seen for support of marijuana legalization. Back around 1990 as many as 50% thought its use should be a crime.

"• Given that the percentage of 12th grade students who support legalization has never exceeded 50% in the 44 years of this study, some of the greater tolerance for marijuana use among adults21 apparently develops after the high school years.

"• The recent trend toward greater tolerance of marijuana use is also seen in the proportion of 12th grade students who support the sale of marijuana to adults, conditional on its use being legalized. In 2018 this proportion was 55%, the same level as in 2017 and the highest level ever recorded by the study (Table 8-8). In past years, support had reached a nadir of 38% in 1989, and then gradually increased to present levels, with a decade-long plateau between 1995 and 2005.

"• It is likely that the growing number of states that have legalized recreational marijuana use for adults plays a role in the increasing tolerance of marijuana use among 12th grade students, who may interpret increasing legalization as a sign that marijuana use is safe and state-sanctioned.

"• In 2018, 9% of 12th graders predicted they would use marijuana if it were legally available (Table 8-8). This is the second highest level recorded for this measure, with the record of 10% set last year. The percentage who predicted they would try marijuana if it were legal reached a historic high in 2018, at 16%. The percentage who reported they would not use marijuana even if it were legal significantly declined to 45%, a record low. Previous to 2018 these outcomes had been fairly similar for all graduating classes. The slight shifts that did occur were attributable mostly to the changing proportions of 12th graders who had actually used marijuana."


Miech, R. A., Johnston, L. D., O’Malley, P. M., Bachman, J. G., Schulenberg, J. E., & Patrick, M. E. (2019). Monitoring the Future national survey results on drug use, 1975–2018: Volume I, Secondary school students. Ann Arbor: Institute for Social Research, The University of Michigan.