title: The effects of antipsychotic medication on factor and cluster structure of neurologic examination abnormalities in schizophrenia.
abstract: This study extends a previous study of the factor structure of the neurologic examination in unmedicated schizophrenia, utilizing cluster analysis and adding a medicated condition. We administered a modified version of the Neurologic Evaluation Scale (NES) on two occasions to 80 patients with schizophrenia or schizoaffective disorder, once while on antipsychotic medications and once while off medication. Data were distilled by combining right- and left-side scores, and by excluding rarely abnormal and unreliable items from the analysis. Principal components analysis yielded an intuitive four-factor solution in the unmedicated condition, but an inscrutable five-factor solution during medication. Cluster analysis revealed three groups: normal, cognitively impaired, and diffusely impaired. These results were also less interpretable with data from the medicated condition. Neurologic performance was better in the medicated than in the unmedicated condition. As is the case with other domains of symptoms and performance in schizophrenia, relationships among neurologic exam variables are altered by the presence of antipsychotic medication.
authors.affiliation: VA Pittsburgh HCS, 7180 Highland Drive, Pittsburgh, PA 15206, USA. ggold@nb.net
authors.forename: Gerald
authors.initials: G
authors.lastname: Goldstein
authors.forename: Richard D
authors.initials: RD
authors.lastname: Sanders
authors.forename: Steven D
authors.initials: SD
authors.lastname: Forman
authors.forename: Thaddeus
authors.initials: T
authors.lastname: Tarpey
authors.forename: John A
authors.initials: JA
authors.lastname: Gurklis
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Van Kammen
authors.forename: Matcheri S
authors.initials: MS
authors.lastname: Keshavan
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000494:pharmacology*; D016000:Cluster Analysis; D005163:Factor Analysis, Statistical; D006801:Humans; D009460:Neurologic Examination / Q000187:drug effects*; D011597:Psychomotor Performance / Q000187:drug effects; D011618:Psychotic Disorders / Q000145:classification / Q000175:diagnosis* / Q000188:drug therapy; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000145:classification / Q000175:diagnosis* / Q000188:drug therapy; D012565:Schizophrenic Psychology
chemical_list: D014150:Antipsychotic Agents