Availability of outpatient substance use disorder treatment programs in the United States.

The purpose of this study was to examine the availability of outpatient substance use disorder (SUD) treatment programs in the United States. A geographic information system (GIS) was used to spatially locate outpatient SUD treatment programs, calculate areas, and determine population density within specific areas. Urban areas were mapped using data from the US Census (2000). Addresses of outpatient SUD treatment programs were obtained from the Facility Locator Web site of the Substance Abuse and Mental Health Services Administration. A 15-mile service catchment around each outpatient SUD treatment program was drawn. The amount of urban area not covered by the service catchment represents the underserved. Total underserved urban area and population without access was computed for each state. Significant variability of underserved urban area and population was observed across the states. Moderate correlations among area and population suggest that some states are more effective in locating SUD treatment programs than other states.