Further validation of PCL-5 symptom validity indices in cross-cultural forensic settings

Objective: The accurate diagnosis of posttraumatic stress disorder (PTSD) is essential in both clinical and forensic contexts. Indices assessing for PTSD symptom invalidity have primarily been validated in Western nations, and more research about the equivalence of these measures is needed when utilized in other countries. Therefore, this study cross-validated existing PTSD Checklist for DSM-5 (PCL-5) symptom validity indices in an African forensic sample. Method: Examinees were 115 African (Ugandan, Kenyan, and Zimbabwean) foreign nationals who had been employed as contractors on U.S. military bases in Iraq and Afghanistan. Examinees were seen for evaluation in a forensic context for claimed PTSD under the purview of the Defense Base Act, a mechanism for pursuing Worker's Compensation type claims. Examinees were classified as credible or non-credible responders based on independent, established symptom validity test findings. Results: The credible and non-credible groups did not differ based on demographic and background variables. Conversely, all three PCL-5 validity indices significantly differentiated the groups with medium effect sizes, and additional validity measures also differentiated groups with medium to large effects, supporting the accuracy of the classifications. Optimal PCL-5 cutoffs closely mirrored those identified in North American samples. When specificity was held at ≥.90, two of the three PCL-5 validity indices yielded sensitivity rates of ≥.30. Conclusions: The findings provide cross‑cultural support for PCL‑5 symptom validity indices and contribute to a growing body of evidence demonstrating their utility across diverse international samples. Consistent patterns across geographic regions suggest these indices may have broader applicability than previously established.