title: Influence of risperidone on balance control in young healthy individuals.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  The objective of this study was to determine the extent to which risperidone at low doses altered balance control in healthy participants.
  
  
  METHODS
  Twelve healthy young adults received, following a randomized double-blind crossover design, a single oral dose of placebo, 1 and 3 mg of risperidone on separate days at least 14 days 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 9 h following drug ingestion.
  
  
  RESULTS
  There is a significant increase in the postural stability item of the ESRS-A parkinsonism subscale at 3 and 6 h following 3 mg of risperidone only when compared to placebo. With regard to balance control, body sway measures were increased at 1 mg of risperidone but more pronounced at 3 mg. The peak effects were observed at 3 h after administration of the drug and had not completely returned to baseline after 9 h.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Groupe de Recherche en Analyse du Mouvement et Ergonomie, Faculté de Médecine, Kinésiologie Université Laval, 2300 Rue de la Terrasse, Québec, QC G1V 0A6, Canada. pco@kin.msp.ulaval.ca
authors.forename: Philippe
authors.initials: P
authors.lastname: Corbeil
authors.forename: Julien
authors.initials: J
authors.lastname: Rodrigue
authors.forename: Martin
authors.initials: M
authors.lastname: Simoneau
authors.forename: Henri
authors.initials: H
authors.lastname: Cohen
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Pourcher
mesh_terms: D000284:Administration, Oral; D000328:Adult; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000009:adverse effects*; D001480:Basal Ganglia Diseases / Q000139:chemically induced*; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D004856:Postural Balance / Q000187:drug effects*; D018967:Risperidone / Q000008:administration & dosage / Q000009:adverse effects*; D013997:Time Factors; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents; D018967:Risperidone