Corresponding Author Information: Claudia Pignolo

Session Abstract: BACKGROUND AND PURPOSE: The Inventory of Problems-29 (IOP-29; Viglione, Giromini, & Landis, 2017) is a self-administered measure of symptom validity and credibility. Recently, a new forced-choice add-on implicit recognition task named the Inventory of Problems-Memory module (IOP-M) was introduced to be used in combination with it. Although available, empirical data strongly support the validity of the IOP-29, research using both the IOP-29 and IOP-M is still scarce. The current study aimed at filling this gap in the literature by administering the IOP-29 and IOP-M to a relatively large, Italian, community sample. METHODS AND MATERIALS: Two studies were conducted, one focused on feigning of depression, and one focused on feigning of PTSD symptoms. In the depression group (n = 239), participants were divided into honest and feigner conditions based on their scores on the Center for Epidemiologic Studies Depression Scale (CES-D): those who scored 20 or higher on the CES-D were asked to take the IOP-29 and IOP-M honestly, whereas those who scored lower than 20 on it were asked to feign depression. Similarly, in the PTSD group (n = 250), participants who scored 33 or higher on the Impact of Event Scale - Revised (IES-R) were asked to take the IOP-29 and IOP-M honestly, whereas participants who scored lower than 33 were asked to feign PTSD. All experimental simulators were given a vignette to facilitate feigning and were warned that if they presented their symptoms too dramatically, their performance would not be believable. ANALYSES: We inspected the effect sizes of the differences between the scores of honest responders and simulators and examined AUC and classification accuracy of both the IOP-29 and IOP-M. RESULTS: The IOP-29 showed very large effect sizes (i.e., d > 3.3) in both groups, whereas the IOP-M showed moderate (d = 1.14) to large (d = 1.41) effect sizes. When the recommended cut score of FDS ‚â• .50 was used, the IOP-29 produced Se = .88, Sp = .97, and OCC = .94 in the PTSD group, and Se = .88, Sp = .96, and OCC = .93 in the depression group. As expected, including the IOP-M yielded increased sensitivity in both groups, reaching .91 and .92 values respectively. CONCLUSIONS: Overall, the results indicate that using both the IOP-29 and IOP-M provides increased classification accuracy rates compared to using the IOP-29 alone.


Claudia Pignolo | Department of Psychology, University of Turin, Turin, Italy

Luciano Giromini, PhD | Department of Psychology, University of Turin, Turin, Italy

Alessandro Zennaro | Department of Psychology, University of Turin, Turin, Italy

Claudia PignoloClaudia Pignolo

Claudia Pignolo is currently an assistant professor at the University of Turin, Italy. Her primary areas of teaching are psychological assessment and psychopathology. Her research focuses on the the empirical validation of the Rorschach and the assessment of malingering and response manipulation.

Dr. GirominiDr. Luciano Giromini

Luciano Giromini, PhD, is an Associate Professor in the Department of Psychology, and core faculty member for the Ph.D. program in Psychological, Anthropological and Educational Sciences of the University of Turin, Italy. He has taught psychological assessment and psychometrics at two Italian and one Californian universities, and is currently the coordinator of the Evidence-Based Psychological Assessment research team of University of Turin. He is one of the authors of the Inventory of Problems (IOP-29 and IOP-M) and Assessment Section Head for the journal Psychological Injury and Law.

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