This study prospectively examines 502 general medical patients for evidence of side-effect of hospitalization unrelated to diagnosis or therapy of acute illness. Symptoms of depressed psychophysiologic functioning (confusion, falling, not eating, and incontinence) unrelated to acute medical diagnoses were found in 8.8% of the patients under 70 and in 40.5% of the elderly population (P less than 0.0001). The rate of medical intervention secondary to these symptoms (psychotropic medications, restraints, nasogastric tubes, and foley catheters) was 37.9% among the young patients and 47.1% in the elderly group (P = 0.4). The sample was too small to permit adequate empirical determination of the complication rate from medical intervention (thrombophlebitis, pulmonary embolus, aspiration pneumonia, urinary tract infection, septic shock) but estimates from the literature indicate that each of the interventions studied entails a complication rate of 25-30%. Combining the observed rate of functional symptoms development and intervention, and the literature rates of complications, yields a risk of complications of 1.0% for the young and 5.7% for the elderly (P less than 0.0001). These data indicate that hospitalized elderly patients are at high risk of developing symptoms of depressed psychophysiology functioning and of sustaining medical intervention as a result of these symptoms, with attendant medical complications. We suggest that in incidence of depressed psychophysiologic function needs to be assessed in patients treated outside the hospital, along with efficacy of treatment outside the hospital, to determine whether there are patients for whom hospitalization is not optimal therapy.