Lower incidence of tardive dyskinesia with risperidone compared with haloperidol in older patients

OBJECTIVE: To compare the 9-month cumulative incidence of tardive dyskinesi a (TD) with risperidone to that with haloperidol in older patients. DESIGN: A prospective longitudinal study. SETTING: An outpatient psychiatric clinic. PARTICIPANTS: Subjects were middle-aged and older (mean age 66 years) patie nts with schizophrenia, dementia, mood disorders, or other conditions with psychotic symptoms or severe behavioral disturbances. Sixty-one patients on risperidone were matched with 61 patients from a larger sample of haloperi dol-treated patients in regard to age, diagnosis, and length of preenrollme nt neuroleptic intake to create clinically comparable groups. The median da ily dose of each medication was 1.0 mg. MEASUREMENTS: Abnormal Involuntary Movement Scale, modified Simpson-Angus' scale for extrapyramidal symptoms, Brief Psychiatric Rating Scale, and Mini -Mental State Examination were administered at baseline, 1 month, and 3, 6, and 9 months. The diagnosis of TD was based on specific research criteria. The raters were blind to the patient's medication status. RESULTS: Life table analysis revealed that patients treated with haloperido l were significantly more likely to develop TD than patients treated with r isperidone (P < .05, Peto-Prentice). CONCLUSIONS: The atypical antipsychotic risperidone is significantly less l ikely to result in TD than the conventional neuroleptic haloperidol in a hi gh-risk group of older patients, at least over a 9-month period.