Geographic market areas for psychiatric and medical outpatient treatment.

The research objective was to measure the variation in the size of a facility's market areas across different diagnostic categories. Specifically, the market area radii for outpatient psychiatric services are compared to the radii for outpatient medical services. Data were collected from the outpatient clinics of the Little Rock Veterans Administration Medical Center. Visits were categorized into 100 diagnostic groups. The market radius for each diagnostic group was defined as the 75th quartile of the distribution of distances traveled. All psychiatric diagnostic groups had significantly (p < 0.05) smaller market area radii than the overall sample radius. The average market area radius across psychiatric illnesses was 62.2 miles, which was significantly (p < 0.05) smaller than the average radius across medical illnesses (90.6 miles). Results suggest that rural patients with mental illness may not receive adequate care and that specialized outreach programs may need to be developed to better serve this population.