The Delirium Rating Scale in a psychogeriatric inpatient setting.

The Delirium Rating Scale (DRS) has been shown to be a valid instrument for identifying and grading the severity of delirium in patients admitted to a general hospital for medical or surgical treatment. However, its accuracy in identifying delirium among elderly patients admitted to a psychiatric hospital for evaluation and treatment of psychiatric illness has not been previously addressed. The DRS was administered to 791 elderly patients who were consecutively admitted to a psychogeriatric unit; 70 met DSM-III-R criteria for delirium. A DRS threshold score of > or = 10 correctly identified delirious patients with a sensitivity of 94% and a specificity of 82%. Both psychosis and cognitive impairment appeared to falsely elevate the DRS score in this population.