The lifetime prevalence of PTSD was highest among Blacks (8.7%), intermediate among Hispanics and Whites (7.0% and 7.4%) and lowest among Asians (4.0%). Differences in risk for trauma varied by type of event. Whites were more likely than the other groups to have any trauma, to learn of a trauma to someone close, and to learn of an unexpected death, but Blacks and Hispanics had higher risk of child maltreatment, chiefly witnessing domestic violence, and Asians, Black men, and Hispanic women had higher risk of war-related events than Whites. Among those exposed to trauma, PTSD risk was slightly higher among Blacks [adjusted odds ratio (aOR) 1.22] and lower among Asians (aOR 0.67) compared with Whites, after adjustment for characteristics of trauma exposure. All minority groups were less likely to seek treatment for PTSD than Whites (aOR range: 0.39–0.61), and fewer than half of minorities with PTSD sought treatment (range: 32.7–42.0%).
Traumatic events, PTSD and treatment-seeking
The National Institute on Alcohol Abuse and Alcoholism Alcohol Use Disorder and Associated Disabilities Interview Schedule DSM-IV version (Grant et al. 2001) was administered to assess lifetime experience of traumatic events and PTSD. In a test–retest study of wave 2 NESARC, reliability for lifetime PTSD was in the fair to good range (k=0.64) (Ruan et al. 2008). The interview queried 27 specific events. Four events were merged with similar events to yield 22 traumatic event types. One event, indirect exposure to a terrorist attack through watching television or listening to the radio, was excluded. These 22 events were then grouped into six major categories based on prior research on PTSD (Breslau et al. 2004b, 2006b) : child maltreatment (three items) ; interpersonal violence (six items) ; war-related traumas (four items) ; other injury or shocking event (five items) ; learning of a trauma to a close friend or relative (three items) ; and learning of an unexpected death (one item).
We first examined whether there were race/ethnic differences in lifetime prevalence of PTSD, using χ2 tests of significance. The second set of analyses addressed race/ethnic differences in exposure to potentially traumatic events. Lifetime prevalence for any event, the six categories of events, and each individual event are reported by race/ethnicity. We used discrete- time survival analysis to estimate race/ethnic differences in the risk of each individual event and the six categories of events, adjusted for gender (Cox, 1972). The dependent variable in these analyses is the age at which each event first occurred; person-time was censored at the age at interview. Because risk for particular traumatic event types varies significantly by age, and the age distribution among respondents is different in the race/ethnic groups, accounting for the underlying risk of traumatic events at each age is important. To see if risk of events differed for race/ethnic groups by gender, we tested gender × race/ethnicity interaction terms for each event. The gender × race/ethnicity interaction term was only significant for risk of war-related events; therefore we analyzed war-related events separately for men and women.