title: Defining trauma: How level of exposure and proximity affect risk for posttraumatic stress disorder.
abstract: OBJECTIVE
  The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) includes significant changes to Criterion A for posttraumatic stress disorder (PTSD), the criterion that defines which events qualify as "traumatic." This systematic review explores the fundamental question of how to define a trauma by reviewing the difference between direct and indirect trauma exposure and the risk for PTSD associated with both exposure types. Direct exposure includes experiencing a trauma firsthand or witnessing a trauma as it occurs to others. In contrast, indirect exposure may occur by learning about the violent or accidental death of a close associate, through secondary narrative accounts (e.g., in service-related professions), or through work-related media reports. This review examines whether indirect trauma exposure can lead to PTSD and the role of proximity in symptom development.
  
  
  METHODS
  We conducted a systematic review of the research assessing changes to PTSD Criterion A in DSM-5, various levels of traumatic exposure, and proximity as a risk factor for PTSD.
  
  
  RESULTS
  Our review indicates that indirect exposure can lead to PTSD, although the probability of developing the disorder from indirect exposure is lower than that from direct exposure. Proximity to a trauma also increases risk, but this may be limited to direct exposure.
  
  
  CONCLUSIONS
  Knowledge of the impact of level of exposure (direct vs. indirect) and proximity will help to better define what events meet PTSD Criterion A. Future research is needed to examine DSM-5's requirement that exposure through media must be related to one's work.
authors.affiliation: Department of Psychology.
authors.forename: Casey L
authors.initials: CL
authors.lastname: May
authors.affiliation: Department of Psychology.
authors.forename: Blair E
authors.initials: BE
authors.lastname: Wisco
mesh_terms: D039721:Diagnostic and Statistical Manual of Mental Disorders; D006801:Humans; D055500:Resilience, Psychological; D012307:Risk Factors; D013313:Stress Disorders, Post-Traumatic / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology*; D013315:Stress, Psychological / Q000175:diagnosis* / Q000453:epidemiology*