Co-occurring Substance Abuse and Mental Health Problems among Homeless Persons: Suggestions for Research and Practice.

Communities throughout the U.S. are struggling to find solutions for serious and persistent homelessness. Alcohol and drug problems can be causes and consequences of homelessness, as well as co-occurring problems that complicate efforts to succeed in finding stable housing. Two prominent service models exist, one known as "Housing First" takes a harm reduction approach and the other known as the "linear" model typically supports a goal of abstinence from alcohol and drugs. Despite their popularity, the research supporting these models suffers from methodological problems and inconsistent findings. One purpose of this paper is to describe systematic reviews of the homelessness services literature, which illustrate weaknesses in research designs and inconsistent conclusions about the effectiveness of current models. Problems among some of the seminal studies on homelessness include poorly defined inclusion and exclusion criteria, inadequate measures of alcohol and drug use, unspecified or poorly implemented comparison conditions, and lack of procedures documenting adherence to service models. Several recent papers have suggested broader based approaches for homeless services that integrate alternatives and respond better to consumer needs. Practical considerations for implementing a broader system of services are described and peer managed recovery homes are presented as examples of services that address some of the gaps in current approaches. Three issues are identified that need more attention from researchers: 1) improving upon the methodological limitations in current studies, 2) assessing the impact of broader based, integrated services on outcome, and 3) assessing approaches to the service needs of homeless persons involved in the criminal justice system.