Trends in Attitudes of US 12th Graders Toward Legalization of Any Illegal Drugs
" From 1975 through 1978, there were modest declines (shifts of five to seven percentage points, depending on the substance) in the proportions of 12th graders who favored legal prohibition of private use of any of the five illicit drugs (see Table 8-7). But by 1990 (12 years later), all of these proportions had increased substantially, with shifts of 8 to 31 percentage points. The proportion who thought marijuana use in private should be prohibited by law more than doubled, from 25% in 1978 to 56% in 1990—a dramatic shift.
" Then, between 1990 and 1997, positions on prohibition of all illicit drug use softened once again, particularly in the case of marijuana use in private. After 1997 these attitudes were fairly stable, or continued to soften slightly. For example, in 2013, 69% thought taking amphetamines or sedatives (barbiturates) in public should be prohibited, down from 77% in 1997.
" One important change in these attitudes that occurred after 2006 is increased tolerance for the use of marijuana in private, as the proportion favoring prohibition declined from 42% in 2006 to 32% in 2013. Tolerance for public use of marijuana increased after 2008, when 70% thought such use should be prohibited, dropping to 61% by 2013.
" The proportions favoring prohibitions on the use in private of some other drugs have also declined since about 2007, including LSD (from 64% to 58% in 2013), amphetamines or sedatives (barbiturates) (from 54% to 49%), and heroin (from 73% to 71%)."
Johnston, L. D., O’Malley, P. M., Bachman, J. G., Schulenberg, J. E. & Miech, R. A. (2014). Monitoring the Future national survey results on drug use, 1975–2013: Volume I, Secondary school students. Ann Arbor: Institute for Social Research, The University of Michigan, pp. 399-400.