title: Progressive brain structural changes mapped as psychosis develops in 'at risk' individuals.
abstract: BACKGROUND
  Schizophrenia and related psychoses are associated with brain structural abnormalities. Recent findings in 'at risk' populations have identified progressive changes in various brain regions preceding illness onset, while changes especially in prefrontal and superior temporal regions have been demonstrated in first-episode schizophrenia patients. However, the timing of the cortical changes and their regional extent, relative to the emergence of psychosis, has not been clarified. We followed individuals at high-risk for psychosis to determine whether structural changes in the cerebral cortex occur with the onset of psychosis. We hypothesized that progressive volume loss occurs in prefrontal regions during the transition to psychosis.
  
  
  METHODS
  35 individuals at ultra-high risk (UHR) for developing psychosis, of whom 12 experienced psychotic onset by 1-year follow-up ('converters'), participated in a longitudinal structural MRI study. Baseline and follow-up T1-weighted MR images were acquired and longitudinal brain surface contractions were assessed using Cortical Pattern Matching.
  
  
  RESULTS
  Significantly greater brain contraction was found in the right prefrontal region in the 'converters' compared with UHR cases who did not develop psychosis ('non-converters').
  
  
  CONCLUSIONS
  These findings show cortical volume loss is associated with the onset of psychosis, indicating ongoing pathological processes during the transition stage to illness. The prefrontal volume loss is in line with structural and functional abnormalities in schizophrenia, suggesting a critical role for this change in the development of psychosis.
authors.affiliation: Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Parkville, Victoria, Australia.
authors.forename: Daqiang
authors.initials: D
authors.lastname: Sun
authors.forename: Lisa
authors.initials: L
authors.lastname: Phillips
authors.forename: Dennis
authors.initials: D
authors.lastname: Velakoulis
authors.forename: Alison
authors.initials: A
authors.lastname: Yung
authors.forename: Patrick D
authors.initials: PD
authors.lastname: McGorry
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Wood
authors.forename: Theo G M
authors.initials: TG
authors.lastname: van Erp
authors.forename: Paul M
authors.initials: PM
authors.lastname: Thompson
authors.forename: Arthur W
authors.initials: AW
authors.lastname: Toga
authors.forename: Tyrone D
authors.initials: TD
authors.lastname: Cannon
authors.forename: Christos
authors.initials: C
authors.lastname: Pantelis
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000473:pathology*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010555:Personality Inventory; D011618:Psychotic Disorders / Q000235:genetics* / Q000473:pathology*; D015203:Reproducibility of Results; D012306:Risk; D055815:Young Adult