Höpfner, HenrikeUysal, BurcuStemmler, MarkAkca, Ali Y. E.Giromini, LucianoUysal, Burcuİnsan ve Toplum Bilimleri Fakültesi, Psikoloji Bölümü2025-01-202025-01-202025Höpfner, H., Uysal, B., Stemmler, M., Akca, A. Y. E. ve Giromini, L. (2025). Cross-cultural applicability of the Inventory of Problems–29 (IOP–29): A pre-registered German replication of Akca, Tepedelen, et al. (2023). Psychiatry, Psychology and Law, 1-14. https://doi.org/10.1080/13218719.2024.24417881321-8719https://doi.org/10.1080/13218719.2024.2441788https://hdl.handle.net/20.500.12154/3164Assessing the credibility of psychological problems in forensic evaluations is crucial. The Inventory of Problems–29 (IOP–29) is becoming a valuable symptom validity test (SVT) worldwide and has been validated in over 15 languages. This study evaluates the German IOP–29 and fills a gap by replicating a study of Akca, Tepedelen, et al. We analysed 384 IOP–29 protocols from 128 German-speaking adults (range = 18–87 years) under three conditions: honest, random and feigned responses (post-traumatic stress disorder, PTSD; depression; schizophrenia). Statistical analyses showed that the False Disorder Probability Score (FDS) effectively discriminated between honest and feigned responses (Hedges g = 3.90), with a sensitivity of .91 and a specificity of .95 at an FDS cut-off value of ≥.50. A new index for detecting careless or random responses also showed promising results. This study confirms the utility of the IOP–29 in the German-speaking population and supports its cross-cultural applicability.eninfo:eu-repo/semantics/openAccessDepressionFeigningGermanIOP–29MalingeringPTSDSchizophreniaSymptom Validity TestArticle11410.1080/13218719.2024.2441788Q3WOS:0013929346000012-s2.0-85214680390Q2