Prevalence and risk factors for homelessness and utilization of mental health services among 10,340 patients with serious mental illness in a large public mental health system

Objective: The authors examined the prevalence of and risk factors for homelessness among all patients treated for serious mental illnesses in a large public mental health system in a 1-year period. The use of public mental health services among homeless persons was also examined. Method: The study included 10,340 persons treated for schizophrenia, bipolar disorder, or major depression in the San Diego County Adult Mental Health Services over a 1-year period ( 1999 - 2000). Analytic methods that adjusted for potentially confounding variables were used. Multivariate logistic regression analyses were used to calculate odds ratios for the factors associated with homelessness, including age, gender, ethnicity, substance use disorder, Medicaid insurance, psychiatric diagnosis, and level of functioning. Similarly, odds ratios were computed for utilization of mental health services by homeless versus not-homeless patients. Results: The prevalence of homelessness was 15%. Homelessness was associated with male gender, African American ethnicity, presence of a substance use disorder, lack of Medicaid, a diagnosis of schizophrenia or bipolar disorder, and poorer functioning. Latinos and Asian Americans were less likely to be homeless. Homeless patients used more inpatient and emergency-type services and fewer outpatient-type services. Conclusions: Homelessness is a serious problem among patients with severe mental illness. Interventions focusing on potentially modifiable factors such as substance use disorders and a lack of Medicaid need to be studied in this population.