MISDIAGNOSING DELIRIUM AS DEPRESSION IN MEDICALLY ILL ELDERLY PATIENTS

Background: Delirium, a common and often overlooked syndrome in acutel y ill elderly patients, may present with signs and symptoms of depress ion. Objective: To determine (1) how often health care providers mista ke delirium for a depressive disorder in older hospitalized patients r eferred to a psychiatric consultation service for depressive symptoms and (2) which signs and symptoms of depression and delirium characteri ze these patients. Subjects: Patients older than 60 years, admitted to a Veterans Affairs teaching hospital, and consecutively referred to a psychiatric consultation service for evaluation and treatment of a de pressive disorder. Methods: The diagnosis of delirium was based on two independent assessments: (1) a clinical interview by a member of the psychiatric consultation service and (2) a structured bedside evaluati on performed by one of the investigators, who was not a member of the psychiatric consultation. service. The investigator administered the C onfusion Assessment Method Instrument, Mini-Mental State Examination, digit span forward, and months of year backward. The investigator also administered the Diagnostic Interview Schedule items for depression t o elicit depressive symptoms. Results: Twenty-eight (41.8%) of the 67 subjects referred for evaluation or treatment of a depressive disorder were found to be delirious. Compared with nondelirious subjects, the delirious subjects were older and more impaired in activities of daily living. The delirious subjects often endorsed depressive symptoms, su ch as low mood (60%), worthlessness (68%), and frequent thoughts of de ath (52%). The referring health care provider had considered delirium in the differential diagnosis of the mood disturbance in only three su bjects. Conclusion: Health care providers should consider the diagnosi s of delirium in hospitalized elderly patients who appear to be depres sed.