title: The Relationship of Intellectual Functioning and Cognitive Performance to Brain Structure in Schizophrenia.
abstract: Schizophrenia (SZ) is often characterized by cognitive and intellectual impairment. However, there is much heterogeneity across individuals, suggesting different trajectories of the illness. Recent findings have shown brain volume differences across subgroups of individuals with psychosis (SZ and bipolar disorder), such that those with intellectual and cognitive impairments presented evidence of early cerebral disruption, while those with cognitive but not intellectual impairments showed evidence of progressive brain abnormalities. Our aim was to investigate the relations of cognition and intellectual functioning with brain structure abnormalities in a sample of SZ compared to unaffected individuals.
  
  
  
  92 individuals with SZ and 94 healthy controls part of the Northwestern University Schizophrenia Data and Software Tool (NUSDAST) underwent neuropsychological assessment and structural magnetic resonance imaging (MRI). Individuals with SZ were divided into subgroups according their estimated premorbid crystallized intellectual (ePMC-IQ) and cognitive performance. Brain volumes differences were investigated across groups.
  
  
  
  SZ with ePMC-IQ and cognitive impairments had reduced total brain volume (TBV), intracranial volume (ICV), TBV corrected for ICV, and cortical gray matter volume, as well as reduced cortical thickness, and insula volumes. SZ with cognitive impairment but intact ePMC-IQ showed only reduced cortical gray matter volume and cortical thickness.
  
  
  
  These data provide additional evidence for heterogeneity in SZ. Impairments in cognition associated with reduced ePMC-IQ were related to evidence of broad brain structural alterations, including suggestion of early cerebral disruption. In contrast, impaired cognitive functioning in the context of more intact intellectual functioning was associated with cortical alterations that may reflect neurodegeneration.
authors.affiliation: Department of Psychological and Brain Sciences, Washington University in St Louis, St Louis, MO, USA.|Laboratório de Psiquiatria Molecular, Hospital de Clínicas de Porto Alegre, Programa de Pós-Graduação em Psiquiatria e Ciências do Comportamento, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Letícia Sanguinetti
authors.initials: LS
authors.lastname: Czepielewski
authors.affiliation: Departments of Psychiatry and Behavioral Sciences, Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Laboratório de Psiquiatria Molecular, Hospital de Clínicas de Porto Alegre, Programa de Pós-Graduação em Psiquiatria e Ciências do Comportamento, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Clarissa S
authors.initials: CS
authors.lastname: Gama
authors.affiliation: Department of Psychological and Brain Sciences, Washington University in St Louis, St Louis, MO, USA.|Departments of Psychiatry and Radiology, Washington University in St Louis, St Louis, MO, USA.
authors.forename: Deanna M
authors.initials: DM
authors.lastname: Barch
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging*; D002540:Cerebral Cortex / Q000000981:diagnostic imaging*; D060825:Cognitive Dysfunction / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007360:Intelligence / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012559:Schizophrenia / Q000000981:diagnostic imaging* / Q000503:physiopathology*
keywords: IQ; MRI; cognition; heterogeneity