title: Extrapyramidal symptoms and cognitive test performance in patients with schizophrenia.
abstract: BACKGROUND
  Movement disorders are common in individuals with schizophrenia, even in those who are not exposed to antipsychotic medications. Extrapyramidal symptoms (EPS) are among the most common abnormal movements in schizophrenia, but their relationship with other features of the illness such as cognition is not well characterized.
  
  
  METHODS
  Three hundred and twenty-five individuals with schizophrenia who were not receiving any antipsychotic or anticholinergic medication and participated in the baseline visit of the Clinical Antipsychotic Treatment of Intervention Effectiveness study were included in the present study. EPSs were assessed using the Simpson-Angus Scale, while cognition was measured with a comprehensive neuropsychological test battery. The relationship between EPS and cognitive test performance was evaluated both dimensionally and categorically.
  
  
  RESULTS
  Greater severity of EPS was significantly associated with worse cognitive test performance evaluated using a composite score. Eighty-six patients were identified as having parkinsonism and these patients performed worse on cognitive tests than non-parkinsonian patients. These findings remained significant even after accounting for other variables such as severity of psychopathology, sedation, akathisia and dyskinesia.
  
  
  CONCLUSIONS
  The present results demonstrate that severity of EPS is reliably linked with poorer scores on tests of cognition. While this may reflect a common pathophysiology underlying neuromotor and neurocognitive deficits, it may also be the case that parkinsonian symptoms such as rigidity and bradykinesia impede test taking ability. Regardless of mechanism, inferences regarding cognitive impairment should take into account the presence of EPS, as well as other variables that may mediate cognitive test findings.
authors.affiliation: Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, Canada; Institute of Medical Science, University of Toronto, Toronto, Canada. Electronic address: gagan.fervaha@utoronto.ca.
authors.forename: Gagan
authors.initials: G
authors.lastname: Fervaha
authors.affiliation: Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, Canada; Institute of Medical Science, University of Toronto, Toronto, Canada; Department of Psychiatry, University of Toronto, Toronto, Canada.
authors.forename: Ofer
authors.initials: O
authors.lastname: Agid
authors.affiliation: Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, Canada; Department of Psychiatry, University of Toronto, Toronto, Canada.
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Takeuchi
authors.affiliation: Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, Canada; Department of Psychiatry, University of Toronto, Toronto, Canada.
authors.forename: Jimmy
authors.initials: J
authors.lastname: Lee
authors.affiliation: Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, Canada; Institute of Medical Science, University of Toronto, Toronto, Canada; Department of Psychiatry, University of Toronto, Toronto, Canada.
authors.forename: George
authors.initials: G
authors.lastname: Foussias
authors.affiliation: Department of Psychology, University of Toronto at Scarborough, Scarborough, Canada.
authors.forename: Konstantine K
authors.initials: KK
authors.lastname: Zakzanis
authors.affiliation: Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, Canada; Institute of Medical Science, University of Toronto, Toronto, Canada; Department of Psychiatry, University of Toronto, Toronto, Canada.
authors.forename: Ariel
authors.initials: A
authors.lastname: Graff-Guerrero
authors.affiliation: Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, Canada; Institute of Medical Science, University of Toronto, Toronto, Canada; Department of Psychiatry, University of Toronto, Toronto, Canada.
authors.forename: Gary
authors.initials: G
authors.lastname: Remington
mesh_terms: D000293:Adolescent; D000328:Adult; D001480:Basal Ganglia Diseases / Q000503:physiopathology* / Q000523:psychology; D003071:Cognition; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D012720:Severity of Illness Index; D055815:Young Adult
keywords: Motor symptoms; Neurocognition; Parkinsonism; Psychomotor slowing; Psychotic disorder; Side effects