Disparities in use of mental health and substance abuse services by persons with co-occurring disorders.

OBJECTIVES: Individuals with co-occurring mental and substance use disorders require psychiatric and substance abuse treatments. A critical question is whether these individuals are treated for both disorders.
METHODS: This study prospectively examined 24-month service utilization patterns of 224 persons with co-occurring disorders who were recruited from crisis residential programs in the mental health treatment system (N=106) and from crisis residential detoxification programs in the substance abuse treatment system (N=118) in San Francisco. Utilization data were collected from the billing-information systems of both treatment systems. Demographic and clinical data were obtained in interviews with participants. Data were analyzed for group differences with chi square tests and logistic, linear, and zero-truncated negative binomial regression.
RESULTS: After the analyses controlled for demographic and clinical factors, participants recruited from the substance abuse treatment system were less likely than those from the mental health treatment system to obtain any mental health services, mental health day treatment, transitional residential care, case management, and other outpatient services (p<.001 for all comparisons). They were more likely to obtain crisis residential detoxification (p=.003), had more days of drug residential treatment (p=.028), but received fewer hours of outpatient services (p=.012).
CONCLUSIONS: There were disparities in patterns of service utilization, although there were no significant diagnostic differences between the two groups. These findings should be valuable in considering systems development and modification. Furthermore, they can contribute to research about factors that underlie results. Study replications should be conducted to assess the robustness of these findings in other locales.