The occurrence and duration of symptoms in elderly patients with delirium

Background. This study attempts to estimate the incidence, prevalence, and average duration of delirium in elderly patients; to assess the sensitivity of DSM-III and DSM-III-R in the diagnosis of delirium; and to compare the estimates of the duration of delirium using DSM-III and DSM-III-R criteria. Methods. A 12-month prospective descriptive study of 168 consecutively admitted patients and 5 additional patients with delirium was conducted in the Geriatric Assessment Unit of a teaching hospital. The duration in days of DSM-III and DSM-III-R symptoms for each delirious patient was assessed by two clinicians. The Barthel Index, Mini-Mental State Examination, and Trezpacz Delirium Symptom Rating Scale scores were also recorded. Results. The prevalence of delirium was 18% and the incidence was 7%. Compared to clinical judgment DSM-III-R showed 100% sensitivity. The mean duration of delirium was 8 ± 9 days (DSM-III-R); the DSM estimate was 7 ± 7 days. Complete symptom recovery was seen in only 52% of surviving patients. Prolonged memory impairment was common. Conclusions. As operationalized in this study, DSM- III-R delirium criteria were more sensitive than DSM-III. Persistent symptoms are common in elderly patients with delirium.