"• In 2019 for the second time in the history of the survey a majority of 12th grade students – 51% – did not favor legally prohibiting marijuana use in public places (the first time was in 2018). The percentage favoring legal prohibitions against use in private was also near a historic low at 21% in 2019, down from 82% in 1990.

"• The majority of 12th graders agree that people should be prohibited by law from using illicit drugs other than marijuana in public. (The questions specified people age 18 or older; presumably proportions would be even higher for those under 18.) For example, in 2019 the percentages agreeing to prohibition are 62% for amphetamines or sedatives (barbiturates), 69% for LSD, and 77% for heroin. Even use in private is opposed by substantial proportions; for example, 40% believe that nonmedical use in private of amphetamines or sedatives (barbiturates) should be illegal, while 46% believe the same for LSD, and 68% believe it about heroin use.

"• In 2019, 36% of 12th graders believe that cigarette smoking in “certain specified public places” should be prohibited by law. Were the question more specific as to the types of public places in which smoking might be prohibited (e.g., restaurants or hospitals), quite different results might have emerged.

"• Less than half (41%) of 12th graders in 2019 think that getting drunk in public should be prohibited.

"• For all drugs included in the question, fewer 12th graders believe that use in private settings should be illegal, as compared with use in public settings. This is particularly true for getting drunk in private (which only 17% think should be illegal vs. 41% for getting drunk in public) and for smoking marijuana in private (which only 21% think should be illegal vs. 49% for smoking marijuana in public places)."

Source

Miech, R. A., Johnston, L. D., O’Malley, P. M., Bachman, J. G., Schulenberg, J. E., & Patrick, M. E. (2020). Monitoring the Future national survey results on drug use, 1975–2019: Volume I, Secondary school students. Ann Arbor: Institute for Social Research, The University of Michigan.