OBJECTIVE: The authors examined the volume and predictors of outpatient
mental health utilization among primary care patients in a large staff-
model health maintenance organization (HMO). METHOD: Consecutive primary
care patients (N = 1,810) were screened by using the 12-item General Health
Questionnaire, and a stratified random sample (N = 373) completed the
28-item General Health Questionnaire and Composite International Diagnostic
Interview. Telephone interviews and computerized records were used to
examine use of mental health services inside and outside the HMO over the
following 3 months. RESULTS: Over 3 months, 6.7% of the screened patients
used mental health services within the HMO. Utilization increased with
higher General Health Questionnaire score (2.9% among those scoring 0,
22.3% among those scoring 8 or more) and decreased with higher
out-of-pocket cost for mental health visits (7.5% for those with no change,
3.3% for those paying $30/visit). Among the interviewed subjects, 5.1% used
mental health services within the HMO (mean = 2.92 visits) and 8.9% used
outside mental health services (mean = 8.86 visits). Use of outside
services was more strongly related to sociodemographic factors, and use of
inside services was more related to severity of psychological disorder.
CONCLUSIONS: Among these subjects, use of mental health care was high and
services purchased outside the HMO exceeded those inside the HMO.
Increasing copayment levels progressively reduced demand without respect to
severity of illness. Attempts to control outpatient mental health costs
must address equity and clinical need.