The National Institute on Alcohol Abuse and Alcoholism, Alcohol Use Disorder and Associated Disabilities Interview Schedule DSM-IV version was used in NESARC to assess psychiatric and substance-use disorders (Grant et al. 2001). Pre-existing MDD, GAD and AUD were coded ‘yes’ if age of onset was lower than age at index event. The assessment of lifetime PTSD begins with a comprehensive list of traumatic events. Respondents who reported more than one event were asked to single out ‘the worst stressful event’ they had ever experienced. The worst event (for respondents with multiple events) or the single event reported by respondents with only one event was the index event for diagnosing PTSD. The groupings of respondents by index events are mutually exclusive: there is one index event per respondent. A distribution of all the index events in NESARC appears elsewhere (Breslau et al. 2010). The following questions were used to ascertain exposure to the traumatic events included in this analysis : (1) ‘Were you EVER in a serious or life threatening accident?’; (2) ‘Were you EVER in a serious fire, tornado, flood,
