The Delirium Rating Scale. Its use in consultation-liaison research

In addition to diagnostic criteria, delirium research requires standardized instruments to measure symptoms. This article reviews the literature about the Delirium Rating Scale (DRS), the most widely used scale to assess delirium that has been translated into at least seven other languages. The DRS has 10 items and is clinician-rated, but 7- or 8-item subscale adaptations have been used for repeated measurements. It has high scale characteristics, including internal consistency, validity, specificity, sensitivity and interrater reliability. The DRS distinguishes delirious from demented, schizophrenic, and depressed patients and is more accurate than cognitive tests in identifying delirium. Scores are sensitive to treatment of delirium. Principal components analyses find one underlying dimension that can be subdivided into two or three components. The DRS has been used in studies of phenomenology, physiology, treatment, outcome, and at-risk populations. Tables summarize details from various studies. The DRS is used clinically and in research. It is currently being revised to enhance its use in phenomenologic and treatment research.