Chronic homelessness and its attendant consequences are experienced more often by those with psychological, physical, and social vulnerabilities. Although there is considerable heterogeneity in the clinical characteristics of people who experience homelessness (Burt et al., 2001), the profile of disabled homeless individuals, the group most likely to fall into chronic homelessness, has not changed much in the last decade. Psychiatric disability, substance abuse, and medical co-morbidities are widespread in the chronically homeless population. In fact, disability resulting from psychiatric and substance use disorders is greater among the chronically homeless population than among other single adults who experience homelessness on a transitional or episodic basis (Kuhn & Culhane, 1998; Burt et al., 2001; Kertesz et al., 2005). Lifetime mental health problems have been found in over 60 percent of chronically homeless people, and greater than 80 percent have experienced lifetime alcohol and/or drug problems (cross-tabulation estimate, Burt et al., 2001). Similar high rates of mental health and substance abuse problems have been reported from housing and service programs designed to serve chronically homeless people (Barrow, Soto, & Cordova, 2004; Robert Rosenheck, personal communication based on unpublished data; Collaborative Initiative to End Chronic Homelessness, 2006). Included among the psychiatric disabilities experienced by homeless people are violent victimization and posttraumatic stress disorder (Metraux & Culhane, 1999).
Medical co-morbidities are commonly found among people who use services designed for people who are chronically homeless (Barrow, Soto, & Cordova, 2004; Robert Rosenheck, personal communication based on unpublished data; Collaborative Initiative to End Chronic Homelessness, 2006). Indeed, the excess morbidity due to mental illness, substance abuse, and medical conditions place homeless people at higher risk of mortality than their housed counterparts. A New York City study found that age-adjusted mortality rates for homeless men and women were approximately four times greater than those found in the general population. Chronicity of homelessness was found to be a strong predictor of mortality among men, even when adjustments were made for age and disability (Barrow et al., 1999). Mortality is greater among younger homeless women compared to those over age 45 years (Cheung & Hwang, 2004). HIV/AIDS is a factor in the increased mortality found in homeless populations. A San Francisco study found that HIV seroprevalence was greater among homeless and marginally housed adults than in the city overall (Robertson et al., 2004). A recent New York City study of the health of sheltered homeless people revealed that the death rate from HIV/AIDS was nine times higher among sheltered single women than among the general population (Kerker et al., 2005). Further evidence comes from the study of Culhane et al. (2001) indicating that people admitted to public shelters in Philadelphia had a three-year rate of subsequent AIDS diagnoses that was nine times that of the citys general population. Other serious infectious diseases such as hepatitis-C (Gelberg et al., 2004) and tuberculosis (Zolopa et al., 1994) and chronic conditions such as asthma and hypertension (Schanzer et al., in press) are found among street and sheltered homeless people.