title: Increased right prefrontal cortical folding in adolescents at risk of schizophrenia for cognitive reasons.
abstract: BACKGROUND
  Two of the strongest predictors of later schizophrenia in the Edinburgh High Risk Study (EHRS) were the presence of schizotypal features and increased right prefrontal lobe cortical folding. We examined the association between these measures in adolescents at enhanced risk of developing schizophrenia due to cognitive impairment.
  
  
  METHODS
  One hundred forty-three adolescents receiving special education were divided into two groups using the cut-off on the Structured Interview for Schizotypy (SIS) which optimally predicted later schizophrenia in the EHRS. Each participant received a structural magnetic resonance imaging scan. Prefrontal tissue volumes and a standard measure of cortical folding, the gyrification index (GI), were determined automatically using automated (A)-GI methodology.
  
  
  RESULTS
  Those who scored above the SIS cut-off had a significantly higher right prefrontal lobe GI compared to those below the cut-off (F = 4.72, p = .03). GI correlated strongly with prefrontal tissue volumes, although when prefrontal volume was added as a covariate to the GI analysis a trend towards a group difference remained evident.
  
  
  CONCLUSIONS
  The level of schizotypal cognitions among adolescents with cognitive impairment identifies a group with the same pattern of cortical folding seen in those with familial risk factors who later develop the disorder. Increased right prefrontal GI may reflect disordered connectivity in individuals with the greatest risk of developing schizophrenia.
authors.affiliation: Division of Psychiatry, School of Molecular and Clinical Medicine, University of Edinburgh, Royal Edinburgh Hospital, Edinburgh, United Kingdom. andrew.stanfield@ed.ac.uk
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Stanfield
authors.forename: T William J
authors.initials: TW
authors.lastname: Moorhead
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Harris
authors.forename: David G C
authors.initials: DG
authors.lastname: Owens
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Lawrie
authors.forename: Eve C
authors.initials: EC
authors.lastname: Johnstone
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D003071:Cognition / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests; D017397:Prefrontal Cortex / Q000473:pathology*; D011569:Psychiatric Status Rating Scales; D012306:Risk; D012559:Schizophrenia / Q000473:pathology* / Q000503:physiopathology*