title: The influence of impaired processing speed on cognition in first-episode antipsychotic-naïve schizophrenic patients.
abstract: BACKGROUND
  Impaired cognition is a prominent feature of schizophrenia. To what extent the heterogeneous cognitive impairments can be accounted for by considering only a single underlying impairment or a small number of core impairments remains elusive. This study examined whether cognitive impairments in antipsychotic-naïve, first-episode schizophrenia patients may be determined by a relative slower speed of information processing.
  
  
  METHODS
  Forty-eight antipsychotic-naïve patients with first-episode schizophrenia and 48 matched healthy controls were administered a comprehensive battery of neuropsychological tests to assess domains of cognitive impairments in schizophrenia. Composite scores were calculated, grouping tests into cognitive domains.
  
  
  RESULTS
  There were significant differences between patients and healthy controls on global cognition and all cognitive domains, including verbal intelligence, processing speed, sustained attention, working memory, reasoning and problem solving, verbal learning and memory, visual learning and memory, and reaction time. All these significant differences, except for verbal intelligence and global cognition, disappeared when processing speed was included as a covariate.
  
  
  CONCLUSIONS
  At the first stage of illness, antipsychotic-naïve patients with schizophrenia display moderate/severe impairments in all the cognitive domains assessed. The results support the contention of a global cognitive dysfunction in schizophrenia that to some extent may be determined by impaired processing speed.
authors.affiliation: Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research (CINS), Copenhagen University Hospital, Psychiatric Center Glostrup, Copenhagen, Denmark. runan@regionsjaelland.dk
authors.forename: R
authors.initials: R
authors.lastname: Andersen
authors.forename: B
authors.initials: B
authors.lastname: Fagerlund
authors.forename: H
authors.initials: H
authors.lastname: Rasmussen
authors.forename: B H
authors.initials: BH
authors.lastname: Ebdrup
authors.forename: B
authors.initials: B
authors.lastname: Aggernaes
authors.forename: A
authors.initials: A
authors.lastname: Gade
authors.forename: B
authors.initials: B
authors.lastname: Oranje
authors.forename: B
authors.initials: B
authors.lastname: Glenthoj
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D001288:Attention / Q000502:physiology; D003071:Cognition / Q000502:physiology*; D005260:Female; D006801:Humans; D007360:Intelligence / Q000502:physiology; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D009483:Neuropsychological Tests; D011340:Problem Solving / Q000502:physiology; D011594:Psychometrics; D011930:Reaction Time / Q000502:physiology*; D012559:Schizophrenia / Q000175:diagnosis* / Q000188:drug therapy; D012565:Schizophrenic Psychology; D014706:Verbal Learning / Q000502:physiology
chemical_list: D014150:Antipsychotic Agents