A description of the nature of psychoactive drugs explains the differences among various substances and their acute and chronic effects. Recent studies of the total population and of high school seniors are reviewed to assess the extent of the use of psychoactive drugs, including alcohol. The history of attitudes toward drug use and legislative reactions to it are outlined, with emphasis on legislation that has unintentionally intensified the current drug problem. A review of scientific perspectives on drug use covers biological, psychological, sociological, and cultural perspectives as well as recent efforts to develop more integrated explanations. Chemically based and nonchemically based treatments are described, with emphasis on findings regarding their effectiveness. The advantages and disadvantages of drug maintenance, the law enforcement approach, and other efforts to deal with the drug problem are analyzed. Recommendations include recognizing both the complexity of the drug abuse problem and the differneces among different substances, educating people about the reasonable and safe use of substances that are no more harmful than alcohol and tobacco, and providing treatment programs for those who no longer wish to use drugs. Additional recommendations, data tables, chapter notes and reference lists, index, and 87 references.