Recent advances in neurobiology and biomedical research technologies have aided the understanding about the most basic molecular and cellular mechanisms involved in this disease. Research has also improved understanding about meeting the needs of individual drug users with a mix of comprehensive treatments, using both medications and behavioral therapies. The spread of HIV infection and AIDS has also had a significant effect on NIDA's treatment research program, because drug abuse is the second largest contributor to AIDS transmission. NIDA is also seeking to improve behavioral treatments for cocaine addicts. Several studies have revealed that drug treatment is cost-effective overall. Each dollar spent on treatment results in savings of $1.28 to $4 in the first year after treatment, plus additional savings in increased productivity, better health, and prevention of problems such as HIV infection and AIDS. More research is needed on costs, organizational issues, and models and strategies for linking drug treatment with primary medical care. Another priority is to attract bright, motivated individuals to research in drug use and addiction. Table, footnote, and 16 references