Influence of risperidone on balance control in young healthy individuals

Abstract

It has previously been shown that impairment of postural stability is a side effect of typical antipsychotic drugs, which are largely administered to control psychosis and behavioral symptoms in elderly patients. Surprisingly, no study has yet addressed this problem with second-generation antipsychotics. The objective of this study was to determine the extent to which risperidone at low doses altered balance control in healthy participants. Twelve healthy young adults received, following a randomized double-blind crossover design, a single oral dose of placebo, 1 and 3mg of risperidone on separate days at least 14days apart. Evaluation of extrapyramidal symptoms using the Extrapyramidal Symptom Rating Scale-abbreviated scoring form (ESRS-A) and measures of postural sway using a force platform were assessed over 9h following drug ingestion. There is a significant increase in the postural stability item of the ESRS-A parkinsonism subscale at 3 and 6h following 3mg of risperidone only when compared to placebo. With regard to balance control, body sway measures were increased at 1mg of risperidone but more pronounced at 3mg. The peak effects were observed at 3h after administration of the drug and had not completely returned to baseline after 9h. Risperidone administered at low doses did not elicit clinically detectable EPS but had significant effects on balance control. A dose-response effect on impairment of balance was observed that followed the expected time course of the drug pharmacokinetics. These results are likely to apply to older or demented individuals who have pre-existing balance control deficit.