This report summarizes a national survey of drug use and related attitudes among American college students and young adults. Its data were derived from an ongoing national research and reporting program. The surveys address two major purposes: (1) to serve a social monitoring function so as to characterize trends in certain behaviors in the population; and (2) to develop knowledge so as to increase our understanding of changes in behavior. Distinctions were drawn among demographic subgroups, recorded incidence of first use, trends in use at lower grade levels, and intensity of drug use. Highlighted are key attitudes about illicit drug use, along with perceptions of certain aspects of the social environment, as potential explanatory factors. Attention was focused on frequent drug use rather than simply reporting those who have ever used various drugs. This strategy serves to differentiate levels of seriousness, or extent, of drug involvement. The last decade witnessed an appreciable decrease in the use of numerous illicit drugs among high-school seniors, accompanied by even larger declines in use among college students and young adults. However, these favorable trends in student populations stalled in 1985, indicating the tenuous nature of these improvements. Of particular concern is the possibility of an increased use of specific drugs accompanied by a general increase in drug abuse by younger cohorts. (RJM)