Ethnic Differences in Symptoms of Post-traumatic Stress after the Exxon Valdez Oil Spill

INTRODUCTION: Previous studies have reported ethnic differences in the prevalence of post-traumatic stress disorder (PTSD), but the reasons for these differences remain unclear. HYPOTHESIS: Ethnic differences in the prevalence of PTSD may reflect ethnic differences in (1) exposure to traumatic events; (2) appraisal of such event as traumatic; and (3) culturally-determined responses to standardized diagnostic instruments, reflecting differences in cultural meanings associated with physical symptoms and idioms of distress. METHODS: Ethnic differences in risk factors and factor structures of PTSD symptoms were examined in 188 Alaskan Natives and 371 Euro-Americans exposed to the Exxon-Valdez oil spill in 1989. RESULTS: High levels of social disruption were associated with PTSD one year after the oil spill in both ethnic groups. However, low family support, participation in spill clean-up activities, and a decline in subsistence activities were significantly associated with PTSD in Alaskan Natives, but not in Euro-Americans. Factor analysis of the Diagnostic Interview Schedule PTSD subscale revealed five factors for both ethnic groups. However, the items comprising these factors were dissimilar. CONCLUSIONS: These results suggest that social disruption is sufficiently traumatic to be associated with symptoms of post-traumatic stress, but that a diagnosis of PTSD must take into consideration local interpretations of these symptoms.