The major goal is to obtain information useful in designing programs that provide treatment and other services to people with severe mental disorders. This project will provide valuable information on a population about whom little is currently known -- namely the severely mentally ill members of a health maintenance organization (HMO). Specifically, HMO members with severe mental disorders will be identified and the services they receive within the HMO will be studied prospectively. The study will monitor the health services utilization of 250 Kaiser Foundation Health Plan enrollees diagnosed as having schizophrenia or bipolar disorder. The HMO's automated pharmacy system will be used to identify members who have been prescribed anti-psychotic drugs or lithium. These persons' medical records will then be reviewed to determine their diagnoses. Persons diagnosed by HMO providers as having schizophrenia or bipolar disorder will become subjects of the study. Additional subjects will be located by reviewing automated hospital discharge abstracts for persons with diagnoses of schizophrenia or bipolar disorder. The subjects' use of general medical and mental health services during the two years of HMO membership subsequent to their identification will be recorded. Disenrollment from the HMO and reasons therefor will also be noted. The severely mentally ill subjects' patterns of medical care utilization within the HMO will be compared with those of matched control HMO members. Finally, the severely mentally ill subjects' duration of membership within the HMO will be compared with that of the controls. These data will allow us to describe the treatment patterns and utilization experiences of severely mentally ill persons enrolled in an HMO. Given the rapid increase in HMO membership, this information is needed by policy makers and health care planners. Since capitated payment systems are now being proposed for the delivery of general medical as well as mental health services to severely mentally ill persons, the data to be generated by this study will have an immediate impact on policy formation.