Staff of infectious disease, substance abuse, mental health, and corrections agencies operate in different fields but share the cadre of clients whose illnesses arise out of, or are worsened by, two highly personal and potentially risky behaviors—substance use and sexual activity. Staff who fully understand the dimensions of the complex connection between sex and substance use can contribute significantly to improved prevention, detection, and treatment measures with these patients and clients.

• It is not easy to provide services to substance-using patients.
  To effectively care for substance-using patients with infectious disease, providers must at least temporarily withhold judgment, not only about intimate behaviors, but also about controversial and stigmatized behaviors, such as IV drug use, and even about controversial methods of treatment. It is partly because of these attitudes that, despite the high coincidence of substance use and risky sexual activity, remarkably few substance abuse or public health prevention, treatment, and counseling programs attend to the connection between substance use and disease transmission.
  
  

• Many providers of care have been only adequately prepared, either through training or experience, to fully address the needs of substance-using patients infected with HIV/AIDS, STDs, TB, or viral hepatitis.
  Many public health service providers don't know how to adequately assess a patient's problems related to substance use; substance abuse treatment staff, in turn, don't know how to adequately assess their patient's problems with respect to infectious disease. Many professionals can benefit from learning how to recognize a potential problem or when to intervene by providing information or conducting screening. They may benefit from learning how to frame a discussion with particular patients. In different communities, the discussion needs to be framed differently, depending on the drugs of choice in the community, the variety of sexual encounters, patients' levels of understanding, and cultural and linguistic barriers that may exist between the client and provider.
  
  

• When these service providers do try to cross the interdisciplinary boundaries of their professions, they often are stymied or frustrated by practice requirements or regulations of the funding streams that support their work but prevent their working in an effective cross-disciplinary way.
  Significant program barriers, such as lack of interagency agreements and inclusion criteria mandated by funding streams, prevent the provision of interdisciplinary services in a collaborative way. Confidentiality laws may at times preclude cross-agency discussion of patients' needs.