B - 134 Validation of the Pcl-5 Rare Items Scale Embedded Symptom Validity Index in a Cross-Cultural Forensic Sample

Abstract Objective Recently, three embedded symptom validity indices were developed for the PTSD Checklist for the DSM-5 (PCL-5). The PCL-5 Rare Item (PRI) scale is one of those indices, which is calculated by summing examinee responses to infrequently endorsed item ratings. Preliminary findings indicate the PRI is effective in a research sample but potentially less effective in a clinical sample. The aim of the current study was to cross-validate the PRI in a cross-cultural forensic sample. Method Examinees were Macedonian and Kosovar contractors (N = 79). Contractors were previously employed at military bases in Afghanistan and Iraq. The examinees underwent defense psychological examinations related to pursuing federal workers compensation claims for PTSD. Examinations were conducted between 2018 and 2023 with appropriately translated instruments and assistance from certified interpreters. Two sets of analyses were performed for this study. First, examinees were categorized as responding validly or invalidly based on their Trauma Symptom Inventory-II Atypical Response Scale (ATR) scores. In a second set of analyses, validity status was based on a more conservative criterion of failing 2+ validity tests. Results Receiver operating characteristic analyses were employed. Area under the curve findings were acceptable (0.74) in both sets of analyses. When invalidity was based on the ATR, a PRI cutoff of 3 resulted in 95% specificity and 35% sensitivity. Similarly, when invalidity was determined by failure of 2+ validity tests, a PRI cutoff of 3 resulted in 95% specificity and 36% sensitivity. Conclusion Results of the current study support the utility of the PRI in a cross-cultural forensic sample.