Prospective study of tardive dyskinesia in the elderly: rates and risk factors.

Objective: The purposes of this study were to investigate the rate (incidence) of tardive dyskinesia in elderly patients beginning treatment with antipsychotic medication and to identify risk factors for development of tardive dyskinesia in this age group.
Method: A group of 261 neuroleptic-naive patients aged 55 or above were identified at the time they were starting antipsychotic drug treatment. This group is the complete study group; a preliminary report based on the first 160 patients was published previously. Patients were evaluated at baseline and followed up at 3-month intervals for periods ranging from 3 to 393 weeks. Assessments included abnormal involuntary movements, extrapyramidal signs, psychiatric symptoms, and medical and drug treatment histories.
Results: The cumulative rates of tardive dyskinesia were 25%, 34%, and 53% after 1, 2, and 3 years of cumulative antipsychotic treatment. A greater risk of tardive dyskinesia was associated with history of ECT treatment, higher mean daily and cumulative antipsychotic doses, and presence of extrapyramidal signs early in treatment. Differences in tardive dyskinesia rates between diagnostic groups found in univariate analyses were attenuated when the authors controlled for these variables.
Conclusions: Tardive dyskinesia rates for patients beginning treatment with conventional antipsychotics in their fifth decade or later are three to five times what has been found for younger patients, despite treatment with lower doses. Alternative treatments need to be investigated.