title: An examination of the relation between combat experiences and combat-related posttraumatic stress disorder in a sample of Connecticut OEF-OIF Veterans.
abstract: BACKGROUND
  Combat exposure is an important risk factor for posttraumatic stress disorder (PTSD). However, little research has examined specific combat experiences associated with PTSD and confirmatory factor analytically (CFA)-derived re-experiencing, avoidance, dysphoria, and hyperarousal symptom clusters.
  
  
  METHODS
  A total of 285 predominantly older National Guard/Reservist OEF-OIF Veterans completed an anonymous mail survey that assessed demographics and deployment history, a broad range of combat experiences, PTSD, and unit and postdeployment social support.
  
  
  RESULTS
  Personally witnessing someone from one's unit or an ally unit being seriously wounded or killed (β = 0.22), and being exposed to "friendly" fire (β = 0.14) and land mines/traps (β = 0.13) were the only three combat experiences associated with severity of combat-related PTSD symptoms, after adjustment for age, relationship status, unit support, postdeployment social support, and other combat experiences. Differential patterns of associations were observed for specific combat experiences in relation to CFA-derived symptom clusters (e.g., experiencing "friendly" fire was associated with re-experiencing and dysphoria symptoms, but not avoidance and hyperarousal symptoms). Personally witnessing someone from one's unit or an ally unit being seriously wounded or killed (odds ratio [OR] = 4.34; 95% confidence interval [CI] = 1.62-11.61) and being exposed to "friendly" fire (OR = 2.94; 95%CI = 1.16-7.47) emerged as independent predictors of a positive screen for probable PTSD.
  
  
  CONCLUSIONS
  Results of this study suggest that witnessing someone in one's unit or ally unit being seriously wounded or killed while in a combat zone and being exposed to "friendly" fire are most strongly associated with combat-related PTSD in this sample of OEF/OIF Veterans. Examination of the relation between specific combat experiences and combat-related PTSD in OEF/OIF Veterans may help inform etiologic models of PTSD, and guide prevention and treatment approaches in this population.
authors.affiliation: National Center for Posttraumatic Stress Disorder, Clinical Neurosciences Division, VA Connecticut Healthcare System, West Haven, CT 06516, USA. robert.pietrzak@yale.com
authors.forename: Robert H
authors.initials: RH
authors.lastname: Pietrzak
authors.forename: Julia M
authors.initials: JM
authors.lastname: Whealin
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Stotzer
authors.forename: Marc B
authors.initials: MB
authors.lastname: Goldstein
authors.forename: Steven M
authors.initials: SM
authors.lastname: Southwick
mesh_terms: D000328:Adult; D003130:Combat Disorders / Q000453:epidemiology* / Q000523:psychology*; D005260:Female; D006801:Humans; D054542:Iraq War, 2003-2011; D008297:Male; D011569:Psychiatric Status Rating Scales; D012044:Regression Analysis; D012307:Risk Factors; D013313:Stress Disorders, Post-Traumatic / Q000453:epidemiology* / Q000523:psychology*; D014728:Veterans