title: Heart rate variability and the relationship between trauma exposure age, and psychopathology in a post-conflict setting.
abstract: BACKGROUND
  Cumulative exposure to potentially traumatic events (PTEs) increases risk for mental distress in conflict-affected settings, but the psychophysiological mechanisms that mediate this dose-response relationship are unknown. We investigated diminished heart rate variability (HRV) - an index of vagus nerve function and a robust predictor of emotion regulation capacity - as a vulnerability marker that potentially mediates the association between PTE exposure, age and symptoms of posttraumatic stress disorder (PTSD), psychological distress and aggressive behavior, in a community sample from Timor-Leste - a post-conflict country with a history of mass violence.
  
  
  METHODS
  Resting state heart rate data was recorded from 45 cases of PTSD, depression and intermittent explosive disorder (IED); and 29 non-case controls.
  
  
  RESULTS
  Resting HRV was significantly reduced in the combined case group compared with non-cases (p = .021; Cohen's d = 0.5). A significant mediation effect was also observed, whereby a sequence of increased age, reduced HRV and elevated PTSD symptoms mediated the association between PTE exposure and distress (B = .06, SE = .05, 95% CI = [.00-.217]) and aggression (B = .02, SE = .02, 95% CI = [.0003-.069])).
  
  
  CONCLUSIONS
  The findings demonstrate an association between diminished resting HRV and psychopathology. Moreover, age-related HRV reductions emerged as a potential psychophysiological mechanism that underlies enhanced vulnerability to distress and aggression following cumulative PTE exposure.
authors.affiliation: The Psychiatry Research and Teaching Unit (PRTU), School of Psychiatry, University of New South Wales, Sydney, Australia. b.liddell@unsw.edu.au.|School of Psychology, University of New South Wales, Sydney, NSW, 2052, Australia. b.liddell@unsw.edu.au.
authors.forename: Belinda J
authors.initials: BJ
authors.lastname: Liddell
authors.affiliation: Discipline of Psychiatry, University of Sydney, Sydney, NSW, Australia.
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Kemp
authors.affiliation: The Psychiatry Research and Teaching Unit (PRTU), School of Psychiatry, University of New South Wales, Sydney, Australia.|St John of God, Richmond Hospital, North Richmond, NSW, 2754, Australia.|Black Dog Institute, School of Psychiatry, University of New South Wales, NSW, Sydney, Australia.
authors.forename: Zachary
authors.initials: Z
authors.lastname: Steel
authors.affiliation: School of Psychology, University of New South Wales, Sydney, NSW, 2052, Australia.
authors.forename: Angela
authors.initials: A
authors.lastname: Nickerson
authors.affiliation: School of Psychology, University of New South Wales, Sydney, NSW, 2052, Australia.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Bryant
authors.affiliation: Academic Mental Health Unit, South Western Sydney Local Health District, Sydney, Australia.
authors.forename: Natalino
authors.initials: N
authors.lastname: Tam
authors.affiliation: The Psychiatry Research and Teaching Unit (PRTU), School of Psychiatry, University of New South Wales, Sydney, Australia.|Academic Mental Health Unit, South Western Sydney Local Health District, Sydney, Australia.
authors.forename: Alvin Kuowei
authors.initials: AK
authors.lastname: Tay
authors.affiliation: The Psychiatry Research and Teaching Unit (PRTU), School of Psychiatry, University of New South Wales, Sydney, Australia.|Academic Mental Health Unit, South Western Sydney Local Health District, Sydney, Australia.
authors.forename: Derrick
authors.initials: D
authors.lastname: Silove
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000374:Aggression / Q000502:physiology / Q000523:psychology; D003220:Conflict, Psychological; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology / Q000503:physiopathology* / Q000523:psychology; D008875:Middle Aged; D013313:Stress Disorders, Post-Traumatic / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology; D013315:Stress, Psychological / Q000453:epidemiology / Q000503:physiopathology* / Q000523:psychology; D049648:Timor-Leste / Q000453:epidemiology; D014754:Violence / Q000523:psychology / Q000706:statistics & numerical data*; D055815:Young Adult
keywords: Age; Aggression; Depression; East Timor; Heart rate variability (HRV); Post-conflict; Posttraumatic stress disorder; Potentially traumatic event (PTE); Timor-Leste; Trauma