Psychometric properties of the Norwegian Impact of Event Scale-revised in a non-clinical sample.

BACKGROUND

Despite the widespread use of the Impact of Event Scale to measure post-traumatic stress symptoms, psychometric evaluations of the scale have revealed mixed findings.

AIM

The aim of the present study is to provide new empirical evidence and examine the factor structure, reliability, and predictive validity of the Norwegian version of the IES-R.

METHODS

Posttraumatic stress symptoms were recorded in a student sample (n=312) 3 weeks after the Southeast Asian tsunami disaster in December 2004. Confirmatory factor analyses of the IES-R behavior items using structural equation modeling (SEM) were performed on four models from existing research.

RESULTS

The original three-factor model of intrusion, avoidance and hyperarousal symptoms exhibited the best goodness-of-fit indices when defined as oblique. The IES-R also revealed satisfactory reliability. Symptom levels of intrusion and avoidance were moderate, while hyperarousal scores were low, with a significant gender difference.

CONCLUSION

Taken together, the IES-R revealed good psychometric properties in this nonclinical student sample and could be a useful instrument to assess and follow-up on PTSD symptoms after a certain identified trauma.