The authors prospectively examined elderly patients diagnosed with major depression with psychotic features (MD-P) and patients diagnosed with dementia of the Alzheimer Type (DAT) for neuroleptic-induced parkinsonism (NIP) during perphenazine treatment. Baseline parkinsonian symptoms did not differ between groups. With treatment, mean NIP score doubled in DAT patients but remained unchanged in the MD-P group. The difference between groups was highly significant and remained so after the effects of age, perphenazine dose, and duration of perphenazine treatment were controlled. Although the mechanisms underlying these differences in NIP development remain to be determined, clinical guidelines for neuroleptic dosages in elderly patients need to account for variability in neuroleptic tolerance between diagnostic groups.
Copyright © 1996 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.