The structure of ICD-11 post traumatic stress disorder in a clinical sample of refugees based on the International Trauma Interview

Background
The ICD-11 proposes fundamental changes to the PTSD diagnostic criteria, prompting thorough validation. While this is ideally carried out based on diagnostic interviews, most—and in the case of transcultural psychiatry all—studies have relied on self-reported measures. In this study, we used the International Trauma Interview (ITI) to assess the factor structure of ICD-11 PTSD symptoms in a sample of trauma-affected refugees.

Method
The ITI was administered with a sample of refugees (n = 198), originating mainly from the Greater Middle East. The symptom ratings were subjected to a confirmatory factor analysis (CFA), comparing the ICD-11 concordant three-factor model with alternative two- and one-factor models.

Results
The overall fit was adequate for both the two- and three-factor models, but favored the two-factor model. Results for both models indicated local misspecifications and that item 5, hypervigilance, displayed a suboptimal loading.

Conclusion
The results generally support the use of the ITI in a severely trauma-affected refugee population, albeit with particular attention needed in the administration of item 5. The superior fit of a two-factor model warrants further testing across populations.