Prediction of use of psychiatric services: application of the CART (classification and regression trees) algorithm.

A computerized recursive partitioning program called Classification and Regression Trees (CART) was used to identify potential high users of services among low-income psychiatric outpatients. Sociodemographic variables, clinical variables (e.g., psychiatric diagnosis and type of presenting complaint), source of referral and the most recent psychiatric treatment setting used were studied. Discharge from inpatient psychiatric treatment right before admission to outpatient psychiatric treatment was found to be the most consistent, the most powerful and the only necessary predictor of high use of outpatient psychiatric services.