OBJECTIVE: This study tested the hypothesis that psychiatric comorbidity measured in medical and surgical general hospital inpatients predicts increased readmissions and days spent rehospitalized at the same hospital up to 4 years after discharge. METHOD: A convenience sample of 273 medical/surgical inpatients aged 18 years and older were given psychological tests during their third to fifth hospital days on medical and surgical units from June 1, 1985, through June 30, 1986. The main outcome measure was the number of medical/surgical readmissions and number of days rehospitalized during a 4-year follow-up at the same institution. RESULTS: Compared to the rest of the study group, the cognitively impaired patients (according to the Mini-Mental State examination) averaged twice as many rehospitalizations and three times as many days rehospitalized at 6- month follow-up and twice as many days rehospitalized at 2-year follow- up. Compared to the rest of the group, the patients who were depressed or who had high interpersonal sensitivity scores at the index admission spent twice as many days rehospitalized during the 4-year follow-up, while the patients with high hostility scores had almost twice as many readmissions. These results remained statistically significant after separate partialing out of the effects of severity of functional impairment, age, cognitive impairment, and number of admissions or days spent hospitalized before the index admission. CONCLUSIONS: Psychiatric comorbidity, previously well documented as contributing to increased length of stay in the general hospital, is associated with increased hospital utilization for at least 4 years after discharge.Abstract Teaser