title: Brain Structure in Neuropsychologically Defined Subgroups of Schizophrenia and Psychotic Bipolar Disorder.
abstract: BACKGROUND
  Neuropsychological impairment is heterogeneous in psychosis. The association of intracranial volume (ICV) and total brain volume (TBV) with cognition suggests brain structure abnormalities in psychosis will covary with the severity of cognitive impairment. We tested the following hypotheses: (1) brain structure abnormalities will be more extensive in neuropsychologically impaired psychosis patients; (2) psychosis patients with premorbid cognitive limitations will show evidence of hypoplasia (ie, smaller ICV); and (3) psychosis patients with evidence of cognitive decline will demonstrate atrophy (ie, smaller TBV, but normal ICV).
  
  
  METHODS
  One hundred thirty-one individuals with psychosis and 97 healthy subjects underwent structural magnetic resonance imaging and neuropsychological testing. Patients were divided into neuropsychologically normal and impaired groups. Impaired patients were further subdivided into deteriorated and compromised groups if estimated premorbid intellect was average or below average, respectively. ICV and TBV were compared across groups. Localized brain volumes were qualitatively examined using voxel-based morphometry.
  
  
  RESULTS
  Compared to healthy subjects, neuropsychologically impaired patients exhibited smaller TBV, reduced grey matter volume in frontal, temporal, and subcortical brain regions, and widespread white matter volume loss. Neuropsychologically compromised patients had smaller ICV relative to healthy subjects, and neuropsychologically normal and deteriorated patient groups, but relatively normal TBV. Deteriorated patients exhibited smaller TBV compared to healthy subjects, but relatively normal ICV. Unexpectedly, TBV, adjusted for ICV, was reduced in neuropsychologically normal patients.
  
  
  CONCLUSIONS
  Patients with long-standing cognitive limitations exhibit evidence of early cerebral hypoplasia, whereas neuropsychologically normal and deteriorated patients show evidence of brain tissue loss consistent with progression or later cerebral dysmaturation.
authors.affiliation: Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN neil.woodward@vanderbilt.edu.
authors.forename: Neil D
authors.initials: ND
authors.lastname: Woodward
authors.affiliation: Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN.
authors.forename: Stephan
authors.initials: S
authors.lastname: Heckers
mesh_terms: D000328:Adult; D001284:Atrophy / Q000473:pathology; D001714:Bipolar Disorder / Q000150:complications / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D003072:Cognition Disorders / Q000209:etiology / Q000473:pathology*; D005260:Female; D066128:Gray Matter / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011618:Psychotic Disorders / Q000150:complications / Q000473:pathology*; D012559:Schizophrenia / Q000150:complications / Q000473:pathology*; D066127:White Matter / Q000473:pathology*; D055815:Young Adult
keywords: brain volume; cognition; neurodevelopmental; neuroprogressive; psychosis