title: Support for the mutual maintenance of pain and post-traumatic stress disorder symptoms.
abstract: BACKGROUND
  Pain and post-traumatic stress disorder (PTSD) are frequently co-morbid in the aftermath of a traumatic event. Although several models attempt to explain the relationship between these two disorders, the mechanisms underlying the relationship remain unclear. The aim of this study was to investigate the relationship between each PTSD symptom cluster and pain over the course of post-traumatic adjustment.
  
  
  METHODS
  In a longitudinal study, injury patients (n=824) were assessed within 1 week post-injury, and then at 3 and 12 months. Pain was measured using a 100-mm Visual Analogue Scale (VAS). PTSD symptoms were assessed using the Clinician-Administered PTSD Scale (CAPS). Structural equation modelling (SEM) was used to identify causal relationships between pain and PTSD.
  
  
  RESULTS
  In a saturated model we found that the relationship between acute pain and 12-month pain was mediated by arousal symptoms at 3 months. We also found that the relationship between baseline arousal and re-experiencing symptoms, and later 12-month arousal and re-experiencing symptoms, was mediated by 3-month pain levels. The final model showed a good fit [chi2=16.97, df=12, p>0.05, Comparative Fit Index (CFI)=0.999, root mean square error of approximation (RMSEA)=0.022].
  
  
  CONCLUSIONS
  These findings provide evidence of mutual maintenance between pain and PTSD.
authors.affiliation: Department of Clinical Psychology and Psychotherapy, Technical University of Dresden, Germany. a.liedl@bzfo.de
authors.forename: A
authors.initials: A
authors.lastname: Liedl
authors.forename: M
authors.initials: M
authors.lastname: O'Donnell
authors.forename: M
authors.initials: M
authors.lastname: Creamer
authors.forename: D
authors.initials: D
authors.lastname: Silove
authors.forename: A
authors.initials: A
authors.lastname: McFarlane
authors.forename: C
authors.initials: C
authors.lastname: Knaevelsrud
authors.forename: R A
authors.initials: RA
authors.lastname: Bryant
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001143:Arousal / Q000502:physiology; D002908:Chronic Disease; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D010147:Pain Measurement; D012720:Severity of Illness Index; D013313:Stress Disorders, Post-Traumatic / Q000453:epidemiology* / Q000523:psychology*; D011795:Surveys and Questionnaires; D055815:Young Adult