The study found that Federal support from the two principal agencies for drug abuse research increased between 1980 and 1990 by more than 200 percent. In contrast, outlays for national defense research and development increased by 83 percent, and nondefense research and development outlays declined by 5 percent in the decade. Drug abuse research funding increased rapidly between 1987 and 1990. Growth has continued steadily since 1983 at the National Institute on Drug Abuse (NIDA), the larger research program. The Office of Justice Programs (OJP) showed an irregular increase from 1981 to 1987, with no substantial increase since the surge in growth in 1987. Of the three categories of drug abuse research funding that were studied -- causality, prevention, and treatment -- NIDA has spent the most on treatment, followed by prevention and causality. Funding for treatment and prevention studies has increased substantially since 1987. OJP has spent as much on prevention studies as on causality and treatment studies combined. Trends in support for each of the three categories were irregular at OJP. Expert researchers GAO interviewed agreed on the importance of further research on the psychological and social/environmental factors that lead to drug abuse. GAO recommends that the Congress review the place of research in national drug control policy and that the Congress examine whether evaluation research is being adequately conducted at the Office of National Drug Control Policy and the major executive agencies responsible for segments of the national drug control program. 6 tables, 11 figures, appended supplementary material, and a 22-item bibliography