title: Comorbidity in posttraumatic stress disorder: a structural equation modelling approach.
abstract: OBJECTIVE
  Posttraumatic stress disorder (PTSD) is associated with high rates of psychiatric comorbidity. Existing theories consider comorbidity as a consequence of PTSD (model 1), PTSD and comorbidity as a consequence of shared factors of vulnerability (model 2), and comorbidity as a consequence of trauma-type specific mechanisms (model 3).
  
  
  METHODS
  To compare the explanatory value of these models, we assessed PTSD (model 1), sense of coherence (model 2) and satisfaction with health (model 3) and symptoms of anxiety and depression as indicators of comorbidity 5 days (t1) and 6 months (t2) postaccident in 225 injured accident survivors. Structural equation models representing models 1 to 3 were tested separately and combined.
  
  
  RESULTS
  Combined, models 1 and 3 explained 82% of the variance of comorbid symptoms at t2. Posttraumatic stress disorder and satisfaction with health (t2) exerted strong influences on comorbid symptoms.
  
  
  CONCLUSIONS
  Comorbidity besides PTSD is best described by an integration of competing explanatory models.
authors.affiliation: Department of Psychiatry, University Hospital, CH-8091 Zurich, Switzerland. lutz.wittmann@usz.ch
authors.forename: Lutz
authors.initials: L
authors.lastname: Wittmann
authors.forename: Hanspeter
authors.initials: H
authors.lastname: Moergeli
authors.forename: Chantal
authors.initials: C
authors.lastname: Martin-Soelch
authors.forename: Hansjoerg
authors.initials: H
authors.lastname: Znoj
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schnyder
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001007:Anxiety / Q000523:psychology; D015897:Comorbidity; D003863:Depression / Q000523:psychology; D005260:Female; D006304:Health Status; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D008960:Models, Psychological; D017060:Patient Satisfaction; D011569:Psychiatric Status Rating Scales; D013313:Stress Disorders, Post-Traumatic / Q000523:psychology*