This report presents findings from a national research and reporting program dealing with drug use and related attitudes of high school seniors. The major topics focus on the current prevalence of drug use among students and trends in drug use since 1975. Also reported are data on the school for first usage, trends in use at earlier grade levels, the intensity of drug use, attitudes among seniors about drug use, and their perceptions of certain aspects of the social environment. Statistics are presented for 11 separate classes of drugs. Findings related to alcohol and smoking are also included, with a particular emphasis on the higher frequency levels of drug use. (JAC)