title: The contribution of threat probability estimates to reexperiencing symptoms: a prospective analog study.
abstract: OBJECTIVE
  Individuals with posttraumatic stress disorder (PTSD) are hypothesized to have a "sense of current threat." Perceived threat from the environment (i.e., external threat), can lead to overestimating the probability of the traumatic event reoccurring (Ehlers & Clark, 2000). However, it is unclear if external threat judgments are a pre-existing vulnerability for PTSD or a consequence of trauma exposure. We used trauma analog methodology to prospectively measure probability estimates of a traumatic event, and investigate how these estimates were related to cognitive processes implicated in PTSD development.
  
  
  METHODS
  151 participants estimated the probability of being in car-accident related situations, watched a movie of a car accident victim, and then completed a measure of data-driven processing during the movie. One week later, participants re-estimated the probabilities, and completed measures of reexperiencing symptoms and symptom appraisals/reactions.
  
  
  RESULTS
  Path analysis revealed that higher pre-existing probability estimates predicted greater data-driven processing which was associated with negative appraisals and responses to intrusions. Furthermore, lower pre-existing probability estimates and negative responses to intrusions were both associated with a greater change in probability estimates. Reexperiencing symptoms were predicted by negative responses to intrusions and, to a lesser degree, by greater changes in probability estimates.
  
  
  CONCLUSIONS
  The undergraduate student sample may not be representative of the general public. The reexperiencing symptoms are less severe than what would be found in a trauma sample.
  
  
  CONCLUSIONS
  Threat estimates present both a vulnerability and a consequence of exposure to a distressing event. Furthermore, changes in these estimates are associated with cognitive processes implicated in PTSD.
authors.affiliation: Department of Psychology, University of British Columbia, 2136 West Mall, V6T 1Z4, Vancouver, British Columbia, Canada.
authors.forename: Marci J
authors.initials: MJ
authors.lastname: Regambal
authors.forename: Lynn E
authors.initials: LE
authors.lastname: Alden
mesh_terms: D000328:Adult; D003071:Cognition; D005260:Female; D006801:Humans; D008016:Life Change Events; D008297:Male; D011939:Mental Recall; D015233:Models, Statistical; D010775:Photic Stimulation; D011336:Probability; D011446:Prospective Studies; D011795:Surveys and Questionnaires