Neuroleptic malignant syndrome in the elderly

Four cases of neuroleptic malignant syndrome (NMS) were identified in a general hospital over a 5-year period. Two cases presented to the psychiatric consultation liaison service, and two were found by a computerized review of discharge diagnoses. Cases were examined for age, sex, administered neuroleptic potency and dose, premorbid history, prodromal symptoms, methods of treatment, and clinical outcome. The mean age of cases was found to be 14 years greater than the age of the non-NMS patient population. All NMS cases had premorbid neuropsychiatric disorders and recognizable prodromal symptoms. The mean neuroleptic dose was significantly lower than in previously reported cases. A systems model integrating premorbid factors, intercurrent illness, and drug effects in pathogenesis is presented.