Volume II presents the comparable results for young adult high school graduates 19-32 years old, as well as college students. Distinctions are made among important demographic subgroups in the surveyed populations based on gender, college plans, region of the country, population density, parents' education, and race/ethnicity. Data on grade of first use, trends in use at lower grade levels, and intensity of drug use also are reported. Key attitudes and beliefs about use of the various drugs have been demonstrated by this study to be important determinants of trends in use over time; therefore, they are also tracked, as are students' perceptions of certain relevant aspects of the social environment, particularly perceived availability, peer norms, use by friends, and exposure to use. Use and trends are reported for the following drugs: marijuana, LSD, amphetamines, inhalants, crack cocaine, cocaine, PCP, heroin, tranquilizers, barbiturates, methaqualone, alcohol, and cigarette smoking. An overview of trend findings shows that from the late 1970's to the early 1990's there were appreciable declines in the use of several illicit drugs among 12th-grade students and even larger declines in their use among American college students and young adults. Explanations for these declines and the implications for drug control policy are discussed. This volume also contains an appendix on how to calculate confidence intervals for point estimates and how to calculate statistics that test the significance of changes over time or of differences between subgroups. 73 tables, 66 figures, and appended supplemental tables for trends by subgroup and trends in prevalence rates for specific drugs within general classes