B - 133 Validation of the PCL-5 Extreme Symptom Scale Embedded Symptom Validity Index in aCross-Cultural Forensic Sample

Abstract Objective Embedded symptom validity indices have recently been developed for the PTSD Checklist for DSM-5 (PCL-5). One of these, the PCL-5 Extreme Symptom (PES) scale is derived by summing extreme responses on the PCL-5 (i.e., endorsed scores of 3 or 4). Preliminary findings support its effectiveness within a clinical sample. In the current study, we aimed to cross-validate the scale with a cross-cultural forensic sample. Method Macedonian and Kosovar contractors (N = 79) who were previously employed at military bases in Afghanistan and Iraq were evaluated between 2018 and 2023. These individuals underwent defense psychological examinations related to a pursuit of federal workers compensation claims for PTSD. Evaluations were performed with translated instruments and assistance from certified interpreters. There were two sets of analyses performed in the current study. Examinees were first determined to be valid or invalid responders based on their Trauma Symptom Inventory-II Atypical Response Scale (ATR) scores. For the second set of analyses, validity status was determined using a more conservative criterion of failing 2+ validity tests. Results Using receiver operating characteristic analyses, the area under the curve was found to be acceptable (0.73) for both sets of analyses. When invalidity was categorized with the ATR, a PES cutoff of 18 resulted in 100% specificity and 15% sensitivity. When invalidity was defined by failure of 2+ validity tests, the PES cutoff was able to be adjusted to 17 resulting in 90% specificity and 26% sensitivity. Conclusion Results of the current study cross-validate the PES with a cross-cultural forensic sample.