Exploration of Cross-Cultural Adaptability of PTSD Among Trauma Survivors in Northern Iraq, Thailand, and the Democratic Republic of Congo: Application of Item Response Theory

Background: There has been an ongoing debate in the trauma field regarding the validity of Post-Traumatic Stress Disorder (PTSD) as a construct among trauma-affected populations displaced from or living in non-Western, low and middle income countries. Some researchers argue that PTSD is a Western construct that is only relevant in Western settings, while others assert that PTSD may be a universal concept.

Purpose: To determine if there are a core set of PTSD symptoms that are applicable across three non-Western low and middle income countries (LMIC). In addition, the aim of the study was to explore if there are PTSD symptoms are endorsed differently according to country.

Methods: Secondary data analysis was conducted from baseline, screening and validity studies among torture survivors in Northern Iraq, sexual violence survivors in the Democratic Republic of Congo (DRC), and Burmese survivors of mass human rights violations in Thailand (N=3183). Uni-dimensional rating scale Item response theory (IRT) analyses were conducted to explore core PTSD symptoms. In addition, IRT differential item functioning analyses were conducted to examine potential symptoms that are endorsed differently based on country.

Results: Compared to both Iraq and Thailand, DRC consistently demonstrated a higher mean of measurement PTSD. This suggests that in general it took less measurement PTSD for the DRC sample to endorse items compared to Iraq or Thailand. Results from the uni-dimensional IRT rating scale model indicated one core item across the whole sample. The item was from the arousal (difficulty concentrating) domain. Results revealed that seven items demonstrated differential item functioning across the countries. Items were from the re-experiencing, numbing, and arousal domains. All items demonstrated statistically significant differential item functioning (p<.0001). However, there was a small to moderate effect size for all of the items.  

Conclusions and Implications:

The small effect size in the potential DIF items suggests that there is little meaningful/clinical difference of the items across country for general screening of PTSD symptoms. However, in clinical settings where a specific assessment for culture is developed or utilized, DIF items should potentially be accounted for and analyzed as having item bias. In general, findings suggest that measurement PTSD has universal as well as country-specific aspects. Future studies should examine the degree to which measurement of PTSD can be improved by accounting for DIF and implications related to relevant trauma assessment and intervention development globally.