Patterns of outpatient mental health care over time: some implications for estimates of demand and for benefit design.

The article examines patterns of starting and continuing outpatient mental health care as a function of time, and the implications of these patterns for estimates of the response of demand to generosity of fee-for-service insurance coverage. The data are from the RAND Health Insurance Experiment (HIE), which acquired a random sample of the nonelderly general population in six U.S. sites. People rarely had more than one episode of use of outpatient mental health services in a year. Persons who used in the prior year had high rates of continuing in treatment, while those without prior use entered treatment at a low, steady rate. Similar patterns of use by former users and nonusers were observed across insurance plans that varied widely in generosity, but the absolute probabilities of use were significantly lower in less generous plans. The probability of use of mental health services expanded significantly over time in the HIE; thus, estimates of demand in a steady state would be higher than those based on the HIE study years.