title: A systematic review of PTSD prevalence and trajectories in DSM-5 defined trauma exposed populations: intentional and non-intentional traumatic events.
abstract: OBJECTIVE
  We conducted a systematic review of the literature to explore the longitudinal course of PTSD in DSM-5-defined trauma exposed populations to identify the course of illness and recovery for individuals and populations experiencing PTSD.
  
  
  METHODS
  We reviewed the published literature from January 1, 1998 to December 31, 2010 for longitudinal studies of directly exposed trauma populations in order to: (1) review rates of PTSD in the first year after a traumatic event; (2) examine potential types of proposed DSM-5 direct trauma exposure (intentional and non-intentional); and (3) identify the clinical course of PTSD (early onset, later onset, chronicity, remission, and resilience). Of the 2537 identified articles, 58 articles representing 35 unique subject populations met the proposed DSM-5 criteria for experiencing a traumatic event, and assessed PTSD at two or more time points within 12 months of the traumatic event.
  
  
  RESULTS
  The mean prevalence of PTSD across all studies decreases from 28.8% (range =3.1-87.5%) at 1 month to 17.0% (range =0.6-43.8%) at 12 months. However, when traumatic events are classified into intentional and non-intentional, the median prevalences trend down for the non-intentional trauma exposed populations, while the median prevalences in the intentional trauma category steadily increase from 11.8% to 23.3%. Across five studies with sufficient data, 37.1% of those exposed to intentional trauma develop PTSD. Among those with PTSD, about one third (34.8%) remit after 3 months. Nearly 40% of those with PTSD (39.1%) have a chronic course, and only a very small fraction (3.5%) of new PTSD cases appears after three months.
  
  
  CONCLUSIONS
  Understanding the trajectories of PTSD over time, and how it may vary by type of traumatic event (intentional vs. non-intentional) will assist public health planning and treatment.
authors.affiliation: Uniformed Services University of Health Sciences, Center for Study of Traumatic Stress, Bethesda, Maryland, USA. patcho.santiago@usuhs.edu
authors.forename: Patcho N
authors.initials: PN
authors.lastname: Santiago
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Ursano
authors.forename: Christine L
authors.initials: CL
authors.lastname: Gray
authors.forename: Robert S
authors.initials: RS
authors.lastname: Pynoos
authors.forename: David
authors.initials: D
authors.lastname: Spiegel
authors.forename: Roberto
authors.initials: R
authors.lastname: Lewis-Fernandez
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Friedman
authors.forename: Carol S
authors.initials: CS
authors.lastname: Fullerton
mesh_terms: D039721:Diagnostic and Statistical Manual of Mental Disorders; D004834:Epilepsy, Post-Traumatic / Q000145:classification* / Q000453:epidemiology* / Q000503:physiopathology*; D006801:Humans; D008137:Longitudinal Studies; D015995:Prevalence; D039781:PubMed; D013997:Time Factors; D014947:Wounds and Injuries / Q000145:classification / Q000150:complications*