The self-report symptom inventory as an instrument for detecting symptom over-reporting: an exploratory study with instructed simulators

The recently developed Self-Report Symptom Inventory (SRSI) intends to provide an alternative approach to the detection of symptom over-reporting. Unlike other measures, the SRSI includes both non-existent symptoms (i.e., pseudosymptoms) and genuine symptoms. Previous research using the German SRSI showed that people who exaggerate their complaints over-endorse both types of symptoms. In the current simulation experiment, we tested whether the Dutch and English SRSI are effective in identifying over-reporting by comparing SRSI scores of an honest group (n = 51) with those of two experimental simulator groups (pain, n = 54; anxiety, n = 53). The pain and anxiety simulators endorsed significantly more genuine symptoms and pseudosymptoms than honest participants (η_p² =.50 and η_p² =.30, respectively). Furthermore, pain and anxiety over-reporters specifically over-endorsed symptoms corresponding to their simulation instructions (Cohen's ds > 0.77). Using the recommended cut-off score, the SRSI detected 48% of pain over-reporters and 73% of anxiety over-reporters, with areas under the curve (AUC) ranging from.88 to.91. These results indicate that the SRSI is a promising tool for identifying over-reporting, but further research with clinical samples is needed.