Outcome of delirium: Part 1. Outcome of delirium diagnosed by DSM-III-R, ICD-10 and CAMDEX and derivation of the Reversible Cognitive Dysfunction Scale among acute geriatric inpatients.

OBJECTIVE: To study performance of DSM-III-R, ICD-10 and CAMDEX diagnoses of delirium as predictors of improvement in mental state in survivors, and to develop a brief rating scale which will predict reversibility of cognitive dysfunction.

DESIGN: Prospective cohort study.

SETTING: Acute geriatric inpatient units.

PATIENTS: A random sample of consecutive acute admissions of patients over the age of 65 (N = 80).

MAIN MEASUREMENTS: Serial assessments of mental state and cognitive function and observational data. Establishment of DSM-III-R, ICD-10, CAMDEX diagnoses.

OUTCOME MEASURE: Patients with more than five points of 20% improvement in Mini Mental State Examination following the most severely impaired assessment operationally designated 'reversible cognitive dysfunction'.

MAIN RESULTS: Diagnoses of delirium by DSM-III-R and ICD-10 do not predict improvement in cognitive function well; CAMDEX does rather better. Discriminant function analysis yielded the Reversible Cognitive Dysfunction Scale (RCDS), a simple clinical scale which accurately predicted improvement. This comprised reduced conscious level, poor attention, poor contact with the patient, incoherent speech, reduced psychomotor activity, lack of awareness of surroundings and poor orientation and memory.

CONCLUSIONS: The concept of and diagnostic criteria for delirium should be reconsidered. The RCDS merits further evaluation.