title: Amygdala volume changes in posttraumatic stress disorder in a large case-controlled veterans group.
abstract: BACKGROUND
  Smaller hippocampal volumes are well established in posttraumatic stress disorder (PTSD), but the relatively few studies of amygdala volume in PTSD have produced equivocal results.
  
  
  OBJECTIVE
  To assess a large cohort of recent military veterans with PTSD and trauma-exposed control subjects, with sufficient power to perform a definitive assessment of the effect of PTSD on volumetric changes in the amygdala and hippocampus and of the contribution of illness duration, trauma load, and depressive symptoms.
  
  
  METHODS
  Case-controlled design with structural magnetic resonance imaging and clinical diagnostic assessments. We controlled statistically for the important potential confounds of alcohol use, depression, and medication use.
  
  
  METHODS
  Durham Veterans Affairs Medical Center, which is located in proximity to major military bases.
  
  
  METHODS
  Ambulatory patients (n = 200) recruited from a registry of military service members and veterans serving after September 11, 2001, including a group with current PTSD (n = 99) and a trauma-exposed comparison group without PTSD (n = 101).
  
  
  METHODS
  Amygdala and hippocampal volumes computed from automated segmentation of high-resolution structural 3-T magnetic resonance imaging.
  
  
  RESULTS
  Smaller volume was demonstrated in the PTSD group compared with the non-PTSD group for the left amygdala (P = .002), right amygdala (P = .01), and left hippocampus (P = .02) but not for the right hippocampus (P = .25). Amygdala volumes were not associated with PTSD chronicity, trauma load, or severity of depressive symptoms.
  
  
  CONCLUSIONS
  These results provide clear evidence of an association between a smaller amygdala volume and PTSD. The lack of correlation between trauma load or illness chronicity and amygdala volume suggests that a smaller amygdala represents a vulnerability to developing PTSD or the lack of a dose-response relationship with amygdala volume. Our results may trigger a renewed impetus for investigating structural differences in the amygdala, its genetic determinants, its environmental modulators, and the possibility that it reflects an intrinsic vulnerability to PTSD.
authors.affiliation: Duke-University of North Carolina Brain Imaging and Analysis Center, 27710, USA. rajendra.morey@duke.edu
authors.forename: Rajendra A
authors.initials: RA
authors.lastname: Morey
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Gold
authors.forename: Kevin S
authors.initials: KS
authors.lastname: LaBar
authors.forename: Shannon K
authors.initials: SK
authors.lastname: Beall
authors.forename: Vanessa M
authors.initials: VM
authors.lastname: Brown
authors.forename: Courtney C
authors.initials: CC
authors.lastname: Haswell
authors.forename: Jessica D
authors.initials: JD
authors.lastname: Nasser
authors.forename: H Ryan
authors.initials: HR
authors.lastname: Wagner
authors.forename: Gregory
authors.initials: G
authors.lastname: McCarthy
mesh_terms: D000328:Adult; D055826:Afghan Campaign 2001-; D000679:Amygdala / Q000473:pathology*; D016022:Case-Control Studies; D003130:Combat Disorders / Q000473:pathology* / Q000523:psychology; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D006624:Hippocampus / Q000473:pathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D054542:Iraq War, 2003-2011; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008889:Military Personnel / Q000523:psychology*; D009657:North Carolina; D009929:Organ Size; D012016:Reference Values; D013313:Stress Disorders, Post-Traumatic / Q000473:pathology* / Q000523:psychology*; D014728:Veterans / Q000523:psychology*