Interviews were conducted in two parts. Part I was administered to all respondents and assessed core DSM-IV mental disorders (n = 73 450 respondents across all surveys). Part II assessed additional disorders and correlates. Questions about traumatic experiences and PTSD were included in Part II, which was administered to 100% of respondents who met lifetime criteria for any Part I disorder and a probability subsample of other Part I respondents (n = 37 255). Part II respondents were weighted to adjust for differential probabilities of selection, selection into Part II, and deviations between the sample and population demographic-geographic distributions. More details about WMH weighting are presented elsewhere (Heeringa et al. 2008).
