title: New onset and persistent symptoms of post-traumatic stress disorder self reported after deployment and combat exposures: prospective population based US military cohort study.
abstract: OBJECTIVE
  To describe new onset and persistence of self reported post-traumatic stress disorder symptoms in a large population based military cohort, many of whom were deployed in support of the wars in Iraq and Afghanistan.
  
  
  METHODS
  Prospective cohort analysis.
  
  
  METHODS
  Survey enrolment data from the millennium cohort (July 2001 to June 2003) obtained before the wars in Iraq and Afghanistan. Follow-up (June 2004 to February 2006) data on health outcomes collected from 50 184 participants.
  
  
  METHODS
  Self reported post-traumatic stress disorder as measured by the posttraumatic stress disorder checklist-civilian version using Diagnostic and Statistical Manual of Mental Disorders, fourth edition criteria.
  
  
  RESULTS
  More than 40% of the cohort were deployed between 2001 and 2006; between baseline and follow-up, 24% deployed for the first time in support of the wars in Iraq and Afghanistan. New incidence rates of 10-13 cases of post-traumatic stress disorder per 1000 person years occurred in the millennium cohort. New onset self reported post-traumatic stress disorder symptoms or diagnosis were identified in 7.6-8.7% of deployers who reported combat exposures, 1.4-2.1% of deployers who did not report combat exposures, and 2.3-3.0% of non-deployers. Among those with self reported symptoms of post-traumatic stress disorder at baseline, deployment did not affect persistence of symptoms.
  
  
  CONCLUSIONS
  After adjustment for baseline characteristics, these prospective data indicate a threefold increase in new onset self reported post-traumatic stress disorder symptoms or diagnosis among deployed military personnel who reported combat exposures. The findings define the importance of post-traumatic stress disorder in this population and emphasise that specific combat exposures, rather than deployment itself, significantly affect the onset of symptoms of post-traumatic stress disorder after deployment.
authors.affiliation: Department of Defense Center for Deployment Health Research at the Naval Health Research Center, San Diego, CA 92106, USA. tyler.c.smith@med.navy.mil
authors.forename: Tyler C
authors.initials: TC
authors.lastname: Smith
authors.forename: Margaret A K
authors.initials: MA
authors.lastname: Ryan
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Wingard
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Slymen
authors.forename: James F
authors.initials: JF
authors.lastname: Sallis
authors.forename: Donna
authors.initials: D
authors.lastname: Kritz-Silverstein
mesh_terms: D000208:Acute Disease; D000328:Adult; D000346:Afghanistan; D002908:Chronic Disease; D003130:Combat Disorders / Q000453:epidemiology*; D030881:Disclosure; D005260:Female; D006801:Humans; D007493:Iraq; D008297:Male; D008875:Middle Aged; D008887:Military Medicine; D011446:Prospective Studies; D012307:Risk Factors; D014481:United States; D014857:Warfare