title: Prospective risk factors for new-onset post-traumatic stress disorder in National Guard soldiers deployed to Iraq.
abstract: BACKGROUND
  National Guard troops are at increased risk for post-traumatic stress disorder (PTSD); however, little is known about risk and resilience in this population.
  
  
  METHODS
  The Readiness and Resilience in National Guard Soldiers Study is a prospective, longitudinal investigation of 522 Army National Guard troops deployed to Iraq from March 2006 to July 2007. Participants completed measures of PTSD symptoms and potential risk/protective factors 1 month before deployment. Of these, 81% (n=424) completed measures of PTSD, deployment stressor exposure and post-deployment outcomes 2-3 months after returning from Iraq. New onset of probable PTSD 'diagnosis' was measured by the PTSD Checklist - Military (PCL-M). Independent predictors of new-onset probable PTSD were identified using hierarchical logistic regression analyses.
  
  
  RESULTS
  At baseline prior to deployment, 3.7% had probable PTSD. Among soldiers without PTSD symptoms at baseline, 13.8% reported post-deployment new-onset probable PTSD. Hierarchical logistic regression adjusted for gender, age, race/ethnicity and military rank showed that reporting more stressors prior to deployment predicted new-onset probable PTSD [odds ratio (OR) 2.20] as did feeling less prepared for deployment (OR 0.58). After accounting for pre-deployment factors, new-onset probable PTSD was predicted by exposure to combat (OR 2.19) and to combat's aftermath (OR 1.62). Reporting more stressful life events after deployment (OR 1.96) was associated with increased odds of new-onset probable PTSD, while post-deployment social support (OR 0.31) was a significant protective factor in the etiology of PTSD.
  
  
  CONCLUSIONS
  Combat exposure may be unavoidable in military service members, but other vulnerability and protective factors also predict PTSD and could be targets for prevention strategies.
authors.affiliation: Minneapolis VA Health Care System, Minneapolis, MN 55417, USA. melissa.polusny@va.gov
authors.forename: M A
authors.initials: MA
authors.lastname: Polusny
authors.forename: C R
authors.initials: CR
authors.lastname: Erbes
authors.forename: M
authors.initials: M
authors.lastname: Murdoch
authors.forename: P A
authors.initials: PA
authors.lastname: Arbisi
authors.forename: P
authors.initials: P
authors.lastname: Thuras
authors.forename: M B
authors.initials: MB
authors.lastname: Rath
mesh_terms: D000293:Adolescent; D000328:Adult; D057189:Checklist; D015331:Cohort Studies; D003130:Combat Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D054542:Iraq War, 2003-2011; D008016:Life Change Events; D008137:Longitudinal Studies; D008297:Male; D008889:Military Personnel / Q000523:psychology* / Q000706:statistics & numerical data; D010555:Personality Inventory / Q000706:statistics & numerical data; D011446:Prospective Studies; D055500:Resilience, Psychological; D012307:Risk Factors; D013313:Stress Disorders, Post-Traumatic / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology*; D011795:Surveys and Questionnaires; D055815:Young Adult