Validity of the Norwegian Version of Inventory of Problems–29 (IoP-29): A simulation study with experimental feigning of depression and a nonclinical control group.

Abstract

Objective: We report on the validation of the Norwegian version of the Inventory of Problems-29 (IoP-29) using an experimental simulation setup with honest responders and responders feigning depression. Method: The sample consisted of 275 participants recruited by convenience by spreading invitational links to participate in the study on social media. They were randomly assigned to either an experimental simulation or an honest condition with the IoP-29. Participants in both conditions were asked to confirm whether they had followed the instructions or not. The honest respondents (n = 138) were asked to respond to the IoP-29 as honestly as they could, whereas the experimental simulators (n = 137) were told to simulate depression based on a case vignette and descriptions of depressive symptoms. Results: We found that participants in the simulation group scored significantly higher than the control group (d = 2.39, p < .000). We found no significant effects from age, gender, or education on the resulting scores. Area under the curve (AUC) for IoP-29 was .94 (SE = .01), meaning a good ability to separate the two conditions. The cutoff for the IoP-False Disorder Score ≥.50 yielded sensitivity = .77, specificity = .93, positive predictive power = .91, negative predictive power = .81, and an overall correct classification = .85. Conclusions: The Norwegian version of IoP-29 demonstrated good validity in discriminating between experimental simulators of depression and a nonclinical control group. Public Significance StatementOur study shows that the Norwegian translation of Inventory of Problems-29 can effectively discriminate between honest nonclinical responders and feigners of depression. This study marks the first step of the validation of the Norwegian IoP-29 version for clinical use.

English versus native language administration of the IOP-29-M produces similar results in a sample of Romanian bilinguals: A brief report.

“…In addition, the fact that no significant gender differences were observed in the memory performance of controls further supports the IOP-M’s robustness to gender, in concordance with studies on other cultures (Blavier et al, 2023; L. Erdodi et al, 2023; Grønnerød et al, 2023; Holcomb et al, 2022).…”

“…Although significant differences between administration languages emerged in controls, the corresponding effect sizes were small, suggesting minimal language effects. There was no difference in the expMAL group, suggesting that in noncredible examinees, the language of administration is not a significant outcome predictor, consistent with previous research supporting the cross-cultural utility of the IOP-29-M (Banovic et al, 2022;De Francisco Carvalho et al, 2021;Giromini, Barbosa, et al, 2020;Grønnerød et al, 2023;Ilgunaite et al, 2021;Šömen et al, 2021). In addition, the fact that no significant gender differences were observed in the memory performance of controls further supports the IOP-M's robustness to gender, in concordance with studies on other cultures (Blavier et al, 2023;Grønnerød et al, 2023;Holcomb et al, 2022).…”

“…This recognition-based PVT also accurately classified invalid performance against free-standing PVTs in English-speaking realworld clinical participants, yielding optimal combinations of classification parameters at the liberal cutoff of ≤30 (L. Erdodi et al, 2023;Holcomb et al, 2022). Moreover, there is evidence accumulating from experimental (Giromini, Barbosa, et al, 2020;Grønnerød et al, 2023) and criterion-groups studies (L. Erdodi et al, 2023) supporting the robustness of the IOP-29-M to demographic variables (e.g., age, gender, education).…”

Assessing the credibility of clinical presentations using performance and symptom validity tests: Current trends and future directions—Part II.

“…In that article, we also highlighted that there appear to be two slightly different research trends when considering emerging empirical studies that focus on symptom validity tests (SVTs) versus performance validity tests (PVTs). Research on SVTs currently seems to focus on validating existing measures (Carvalho et al, 2021;Geurten et al, 2018;Giromini et al, 2018;Grønnerød et al, 2023;Pignolo et al, 2023;Roma et al, 2020;van Helvoort et al, 2019) and developing new ones in the form of both This document is copyrighted by the American Psychological Association or one of its allied publishers.…”

“…In that article, we also highlighted that there appear to be two slightly different research trends when considering emerging empirical studies that focus on symptom validity tests (SVTs) versus performance validity tests (PVTs). Research on SVTs currently seems to focus on validating existing measures (Carvalho et al, 2021; Geurten et al, 2018; Giromini et al, 2018; Grønnerød et al, 2023; Pignolo et al, 2023; Roma et al, 2020; van Helvoort et al, 2019) and developing new ones in the form of both embedded (Bodapati et al, 2019; Crighton et al, 2014; Fuermaier et al, 2023; Shura et al, 2023; Vanderploeg et al, 2014) and free-standing SVTs (Merten et al, 2016; Viglione et al, 2017). In contrast, perhaps because there are many more well-validated and widely used PVTs than SVTs (Giromini et al, 2022; Sweet et al, 2021), current PVT research seems to focus more on expanding the knowledge base on existing instruments, in the form of introducing new trials (C.…”