title: Hippocampal Shape Abnormalities Predict Symptom Progression in Neuroleptic-Free Youth at Ultrahigh Risk for Psychosis.
abstract: BACKGROUND
  Hippocampal abnormalities have been widely studied in schizophrenia spectrum populations including those at ultrahigh risk (UHR) for psychosis. There have been inconsistent findings concerning hippocampal morphology prior to and during the transition to psychosis, and little is known about how specific subregions are related to the symptom progression.
  
  
  METHODS
  A total of 80 participants (38 UHR and 42 healthy controls) underwent a 3T MRI scan, as well as structured clinical interviews. Shape analysis of hippocampi was conducted with FSL/FIRST vertex analysis to yield a localized measure of shape differences between groups. A subgroup of the sample (24 UHR and 24 controls) also returned for a 12-month clinical follow-up assessment.
  
  
  RESULTS
  The UHR group exhibited smaller hippocampal volumes bilaterally, and shape analysis revealed significant inversion in the left ventral posterior hippocampus in the UHR group. Greater inversion in this subregion was related to elevated symptomatology at baseline and increased positive symptoms, negative symptoms, and impaired tolerance to normal stress 12 months later. These results did not hold when left hippocampal volume was used as a predictor instead.
  
  
  CONCLUSIONS
  This represents the first study to use vertex analysis in a UHR sample and results suggest that abnormalities in hippocampal shape appear to reflect underlying pathogenic processes driving the progression of illness. These findings suggest that examining shape and volume may provide an important new perspective for our conception of brain alterations in the UHR period.
authors.affiliation: Department of Psychology and Neuroscience, Center for Neuroscience, and derek.dean@colorado.edu.
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Dean
authors.affiliation: Institute for Cognitive Science, University of Colorado Boulder, Boulder, CO;
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Orr
authors.affiliation: Department of Psychology and Neuroscience.
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Bernard
authors.affiliation: Department of Psychology and Neuroscience.
authors.forename: Tina
authors.initials: T
authors.lastname: Gupta
authors.affiliation: Department of Psychology and Neuroscience, Center for Neuroscience, and.
authors.forename: Andrea
authors.initials: A
authors.lastname: Pelletier-Baldelli
authors.affiliation: Department of Psychology and Neuroscience.
authors.forename: Emily E
authors.initials: EE
authors.lastname: Carol
authors.affiliation: Department of Psychology, Northwestern University, Evanston, IL.
authors.forename: Vijay A
authors.initials: VA
authors.lastname: Mittal
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D018450:Disease Progression; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size; D062706:Prodromal Symptoms; D011379:Prognosis; D011618:Psychotic Disorders / Q000473:pathology*; D012306:Risk; D012559:Schizophrenia / Q000473:pathology*; D055815:Young Adult
keywords: Hippocampus; MRI; psychosis; shape analysis; ultra-high risk; vertex analysis