In this study, the authors determined whether mental health status affects the use of general medical services, with and without adjustment for the correlated effects of general health perceptions and physical health status on such use. Data were used from the RAND Health Insurance Experiment, which has information on up to 5 years of use of medical services by a nonelderly, civilian, general population. Health status and other covariates were assessed by self-administered questionnaires at enrollment. In the absence of statistical control for general and physical health status, worse mental health status-whether assessed by a global self-report measure or its two component parts, psychological well-being and psychological distress-significantly increased the use of both inpatient and outpatient general medical services. After controlling for general health perceptions, physical health status, demographic factors, and insurance plan coverage, the effects of mental health status on use are reduced, but not eliminated. Psychological distress and psychological well-being retained independent effects on total medical expenses.