before AIDS (Selwyn et al., 1992; Selwyn and O'Connor, 1992). Preliminary data suggest that certain clinical conditions (e.g., tuberculosis) may hasten disease progression in HIV-infected drug users (Farizo et al., 1992; Mientjes et al., 1992; IOM, 1994); and it has been hypothesized that the immunosuppressive or immunostimulatory effects of psychoactive drugs may influence HIV disease progression (Des Jarlais, 1991). Further research is needed to determine the possible impact of cofactors in HIV disease progression among drug abusers.

Understanding the natural history of HIV among IDUs and the increased risk of certain infections and complications is important for developing and providing effective treatment strategies for drug users. The medical complications of injection drug use may mimic, obscure, mask, or coexist with HIV-related infection and conditions, resulting in difficulties in diagnosis and more costly interventions. Research is needed to examine the effects of antiretroviral and other HIV medications on the occurrence of bacterial infections in drug users and to explore possible interactions of HIV medications with abused psychoactive drugs. Without proper knowledge of the etiological relationship between drug abuse and the course and progression of HIV disease, efforts at preventing transmission will continue to fall short of addressing the epidemic adequately.

As research continues to address the best treatment modalities for HIV-infected drug abusers, studies are needed on the issues of access and utilization of treatment that are unique to that population. Research has established that drug abuse treatment is associated with a reduction in HIV transmission or related risk behaviors (see Chapter 7).

The link between the need to treat both AIDS and drug abuse has heightened awareness of drug abuse treatment-a significant step toward the integration of drug abuse treatment into mainstream medical