title: Cognition in schizophrenia and schizo-affective disorder: impairments that are more similar than different.
abstract: BACKGROUND
  Cognition is increasingly being recognized as an important aspect of psychotic disorders and a key contributor to functional outcome. In the past, comparative studies have been performed in schizophrenia and schizo-affective disorder with regard to cognitive performance, but the results have been mixed and the cognitive measures used have not always assessed the cognitive deficits found to be specific to psychosis. A set of optimized cognitive paradigms designed by the Cognitive Neuroscience Test Reliability and Clinical Applications for Schizophrenia (CNTRACS) Consortium to assess deficits specific to schizophrenia was used to measure cognition in a large group of individuals with schizophrenia and schizo-affective disorder.
  
  
  METHODS
  A total of 519 participants (188 with schizophrenia, 63 with schizo-affective disorder and 268 controls) were administered three cognitive paradigms assessing the domains of goal maintenance in working memory, relational encoding and retrieval in episodic memory and visual integration.
  
  
  RESULTS
  Across the three domains, the results showed no major quantitative differences between patient groups, with both groups uniformly performing worse than healthy subjects.
  
  
  CONCLUSIONS
  The findings of this study suggests that, with regard to deficits in cognition, considered a major aspect of psychotic disorder, schizophrenia and schizo-affective disorder do not demonstrate major significant distinctions. These results have important implications for our understanding of the nosological structure of major psychopathology, providing evidence consistent with the hypothesis that there is no natural distinction between cognitive functioning in schizophrenia and schizo-affective disorder.
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA.
authors.forename: A
authors.initials: A
authors.lastname: Owoso
authors.forename: C S
authors.initials: CS
authors.lastname: Carter
authors.forename: J M
authors.initials: JM
authors.lastname: Gold
authors.forename: A W
authors.initials: AW
authors.lastname: MacDonald
authors.forename: J D
authors.initials: JD
authors.lastname: Ragland
authors.forename: S M
authors.initials: SM
authors.lastname: Silverstein
authors.forename: M E
authors.initials: ME
authors.lastname: Strauss
authors.forename: D M
authors.initials: DM
authors.lastname: Barch
mesh_terms: D000328:Adult; D003072:Cognition Disorders / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D061212:Memory, Episodic; D008570:Memory, Short-Term / Q000502:physiology; D011939:Mental Recall / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D011618:Psychotic Disorders / Q000150:complications / Q000503:physiopathology*; D012559:Schizophrenia / Q000150:complications / Q000503:physiopathology*; D014796:Visual Perception / Q000502:physiology