The syndemic between HIV/AIDS, severe mental illnesses and substance abuse or dependence is becoming routinely recognized both within the empirical literature as well as within the wider domains of public policy, public health, and intervention science. As such, efforts are being redoubled to address issues of testing for those at risk but not yet diagnosed as well as to increase treatment adherence for non-adherent HIV positive persons who are increasingly identified as complex patients, or those who present with multiple co-morbidities that span provider types and place higher burdens on service utilization. Interventions designed to link these complex patients with appropriate and cost effective treatments represent a nascent but growing research domain.