Detection of Feigning of Different Symptom Presentations With the PAI and IOP-29

This study examined the effectiveness of the negative distortion measures from the Personality Assessment Inventory (PAI) and Inventory of Problems-29 (IOP-29), by investigating data from a community and a forensic sample, across three different symptom presentations (i.e., feigned depression, posttraumatic stress disorder [PTSD], and schizophrenia). The final sample consisted of 513 community-based individuals and 288 inmates (total N = 801); all were administered the PAI and the IOP-29 in an honest or feigning conditions. Statistical analyses compared the average scores of each measure by symptom presentation and data source (i.e., community vs. forensic sample) and evaluated diagnostic efficiency statistics. Results suggest that the PAI Negative Impression Management scale and the IOP-29 are the most effective measures across all symptom presentations, whereas the PAI Malingering Index and Rogers Discriminant Function generated less optimal results, especially when considering feigned PTSD. Practical implications are discussed.