Tardive dyskinesia in neuroleptic medicated mentally handicapped subjects.

Sixty-seven neuroleptic medicated mentally handicapped subjects in a hospital were rated on two occasions for abnormal involuntary movements on three scales: Abnormal Involuntary Movements (AIMS), Rockland and Parkinsonism scales, with 6 months between each assessment. Inter-rater and test-retest reliabilities were high. The data from the second assessment was analyzed. Prevalence of tardive dyskinesia (TD) was 21% on AIMS, 42% on the Rockland scale; 60% had parkinsonism. Multiple stepwise regression analysis revealed that age, sex, current neuroleptic and anticholinergic dose, antiepileptic medication, psychosis, cumulative anticholinergic dose were not significant predictors of TD as determined by AIMS. Parkinsonism and cumulative neuroleptic dose were significant predictors of and correlated positively with AIMS score. TD subjects formed 35% of the parkinsonian group. Overt brain damage was not a significant predictor of AIMS score and the difference between the neuroleptic medicated and neuroleptic free group on AIMS scores was highly significant.