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

OBJECTIVE

To compare the 9-month cumulative incidence of tardive dyskinesia (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) patients 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 haloperidol-treated patients in regard to age, diagnosis, and length of pre-enrollment neuroleptic intake to create clinically comparable groups. The median daily 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 haloperidol were significantly more likely to develop TD than patients treated with risperidone (P < .05, Peto-Prentice).

CONCLUSIONS

The atypical antipsychotic risperidone is significantly less likely to result in TD than the conventional neuroleptic haloperidol in a high-risk group of older patients, at least over a 9-month period.