title: Insomnia severity is associated with a decreased volume of the CA3/dentate gyrus hippocampal subfield.
abstract: BACKGROUND
  Prolonged disruption of sleep in animal studies is associated with decreased neurogenesis in the dentate gyrus. Our objective was to determine whether insomnia severity in a sample of posttraumatic stress disorder (PTSD) patients and control subjects was associated with decreased volume in the CA3/dentate hippocampal subfield.
  
  
  METHODS
  Volumes of hippocampal subfields in 17 veteran men positive for PTSD (41 +/- 12 years) and 19 age-matched male veterans negative for PTSD were measured with 4-T magnetic resonance imaging. Subjective sleep quality was measured by the Insomnia Severity Index (ISI) and the Pittsburgh Sleep Quality Index.
  
  
  RESULTS
  Higher scores on the ISI, indicating worse insomnia, were associated with smaller volumes of the CA3/dentate subfields (r = -.48, p < .01) in the combined sample. Adding the ISI score as a predictor for CA3/dentate volume to a hierarchical linear regression model after first controlling for age and PTSD symptoms accounted for a 13% increase in incremental variance (t = -2.47, p = .02).
  
  
  CONCLUSIONS
  The findings indicate for the first time in humans that insomnia severity is associated with volume loss of the CA3/dentate subfields. This is consistent with animal studies showing that chronic sleep disruption is associated with decreased neurogenesis and dendritic branching in these structures.
authors.affiliation: Mental Health Service, DVA Medical Center, San Francisco, California 94121, USA. Thomas.Neylan@ucsf.edu
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Neylan
authors.forename: Susanne G
authors.initials: SG
authors.lastname: Mueller
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Metzler
authors.forename: Maryann
authors.initials: M
authors.lastname: Lenoci
authors.forename: Diana
authors.initials: D
authors.lastname: Truran
authors.forename: Charles R
authors.initials: CR
authors.lastname: Marmar
authors.forename: Michael W
authors.initials: MW
authors.lastname: Weiner
authors.forename: Norbert
authors.initials: N
authors.lastname: Schuff
mesh_terms: D000328:Adult; D000818:Animals; D018891:Dentate Gyrus / Q000254:growth & development / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D055495:Neurogenesis / Q000502:physiology; D012892:Sleep Deprivation / Q000473:pathology* / Q000523:psychology; D007319:Sleep Initiation and Maintenance Disorders / Q000503:physiopathology / Q000523:psychology / Q000628:therapy; D013313:Stress Disorders, Post-Traumatic / Q000503:physiopathology / Q000523:psychology; D014728:Veterans / Q000523:psychology