title: The influence of pre-deployment cognitive ability on post-traumatic stress disorder symptoms and trajectories: The Danish USPER follow-up study of Afghanistan veterans.
abstract: OBJECTIVE
  New trajectories of PTSD symptoms have recently been identified in war exposed army veterans. The aim of this army veterans study was to examine whether pre-deployment cognitive ability is associated with the risk of developing PTSD symptoms or non-resilient PTSD trajectories.
  
  
  METHODS
  Follow up study in 428 Danish soldiers, deployed to Afghanistan in 2009, who were assessed at six occasions from pre-deployment to three years post-deployment. Pre-deployment vulnerabilities, deployment and homecoming stressors were measured. Pre-deployment cognitive test scores on Børge Priens Prøve (based on logical, verbal, numerical and spatial reasoning) were converted to a mean of 100 and with a standard deviation of 15.
  
  
  RESULTS
  Higher pre-deployment cognitive ability scores were associated with lower risk of PTSD symptoms as assessed by the Posttraumatic Stress Disorder Checklist-Civilian Version (PCL-C) 2.5 years post-deployment (OR=0.97; 95% CI 0.95-1.00) after adjustment for educational length, baseline PCL-C score and perceived war-zone stress. Compared to a resilient trajectory, a non-resilient relieved-worsening trajectory (high baseline mental symptoms, being symptom free during deployment and a drastic increase in PTSD symptoms at the final assessments of PTSD symptoms) had significantly lower cognitive scores by a mean difference of 14.5 (95% CI 4.7-24.3). This trajectory (n=9) comprised 26.5% of soldiers with moderate-severe PTSD symptoms 2.5 years post-deployment.
  
  
  CONCLUSIONS
  We confirmed an inverse association between pre-deployment cognitive ability and risk of PTSD symptoms, and observed significantly lower mean pre-deployment cognitive scores in one non-resilient PTSD trajectory. If replicated, this might inform relevant prevention efforts for soldiers at pre-deployment.
authors.affiliation: Mental Health center Copenhagen, University of Copenhagen, Kildegårdsvej 28, 2900 Hellerup, Denmark. Electronic address: holger.jelling.soerensen@regionh.dk.
authors.forename: Holger J
authors.initials: HJ
authors.lastname: Sørensen
authors.affiliation: Research and Knowledge Center, The Danish Veteran Center, Garnisonen 1, 4100 Ringsted, Denmark.
authors.forename: Søren B
authors.initials: SB
authors.lastname: Andersen
authors.affiliation: Research and Knowledge Center, The Danish Veteran Center, Garnisonen 1, 4100 Ringsted, Denmark.
authors.forename: Karen-Inge
authors.initials: KI
authors.lastname: Karstoft
authors.affiliation: Mental Health center Copenhagen, University of Copenhagen, Kildegårdsvej 28, 2900 Hellerup, Denmark; Research and Knowledge Center, The Danish Veteran Center, Garnisonen 1, 4100 Ringsted, Denmark.
authors.forename: Trine
authors.initials: T
authors.lastname: Madsen
mesh_terms: D000328:Adult; D055826:Afghan Campaign 2001-; D003071:Cognition; D003718:Denmark; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008889:Military Personnel / Q000523:psychology; D009784:Occupational Diseases / Q000523:psychology*; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors; D013313:Stress Disorders, Post-Traumatic / Q000523:psychology*; D014728:Veterans / Q000523:psychology*
keywords: PTSD symptoms; Pre-deployment cognitive ability; Predictors; Soldiers; Trajectories