Hallmarks of posttraumatic stress: symptom Z-scores in a tsunami-affected tourist population

Abstract

Background: To date, little research has been published on the prominence of the various psychiatric symptoms that result from exposure to a natural disaster. In our study of stress-related symptoms among Norwegian tourists who were repatriated after the 2004 southeast Asian tsunami, we evaluated to what extent symptom scores differed between individuals who were exposed to the disaster and those who were not.

Methods: Participants (n = 899) completed a questionnaire via post 6 months after the disaster. The participants were categorized according to their level of exposure to the disaster: danger exposed (caught or chased by the waves), nondanger exposed (other disaster-related stressors) and not exposed. Symptoms were assessed by the General Health Questionnaire (GHQ-28), the Post Traumatic Symptom Scale (PTSS-10), and the Impact of Event Scale - Revised (IES-R). We used z-transformation of symptom scores (Z-scores) to evaluate the extent to which symptom scores among disaster-exposed individuals differed from those in the nonexposed reference group.

Results: The IES-R revealed the greatest differences between nonexposed and disaster-exposed individuals. Hyperarousal was the most prominent symptom cluster that related to disaster exposure, followed by intrusion and then avoidance. Symptoms of anxiety, social dysfunction, withdrawal, somatization and feelings of guilt were more closely linked to exposure than were symptoms of depression.

Conclusions: Our results indicate that symptoms of hyperarousal may be more closely linked to acute exposure to a natural disaster such as a tsunami than other symptoms of psychological distress.