This research examines how extending health insurance coverage to the previ
ously uninsured impacts outpatient mental health treatment use among adults
with different needs. Using data from the Epidemiologic Catchment Area Stu
dy and the 1987 National Medical Expenditure Survey, I develop simulations
based on estimates of treatment demand. I find that insurance substantially
increases demand by the mentally ill, but increased coverage alone cannot
meet their treatment needs. Those in better mental health account for signi
ficant proportions of additional demand when coverage is expanded. Policies
intended to increase access to mental health treatment among targeted grou
ps should carefully consider the costs of increased use by other people.