PTSD prevalence was determined for three periods: (a) lifetime (i.e., met criteria at any time), (b) past year (i.e., met criteria during the past 12 months), and (c) past 6 months (i.e., met criteria during the past 6 months). Lifetime, past-year, and past-6-month prevalence was calculated using Composite Event and Same Event definitions based on both the DSM-IV and the DSM-5.
