鈥� We studied 779 walk-in psychiatric patients presenting to 32 first- or second-year residents and 772 patients presenting to 25 third-year residents or attending physicians as to the decision to admit to the hospital or to administer medication to those not admitted. There were no significant demographic or clinical differences between patients presenting to the two groups. The more experienced staff admitted half as many patients and treated serious depression with tricyclics twice as frequently. Inexperienced psychiatrists used hospitalization more frequently when these patients suffered from suicidal ideation, hallucinations, delusions, and inability to cope. When the training procedure was modified and second-year residents were introduced into a more structured setting, their decision-making quickly approached that of third-year residents and attending physicians. We suggest that specific training can modify decisionmaking, where general clinical experience may not. Implications for resident and medical student training are discussed.