Detecting simulated symptoms in chronic pain and fibromyalgia: A two-study evaluation of the Italian version of the Self-Report Symptom Inventory.

Abstract

The subjective nature of pain complicates objective verification, often leading to noncredible symptom reports in compensable settings. Across two studies, we evaluated the Italian Self-Report Symptom Inventory (SRSI-It) in distinguishing healthy individuals, simulators, and fibromyalgia patients. In Study 1, we assigned 958 participants to the honest (n = 482) or simulator group (n = 476). Simulators reported higher scores on genuine and pseudosymptoms. A cut score > 6 showed 92% specificity and 64% sensitivity; > 9 raised specificity to 95%. The SRSI-It identified 62% and 58% of simulators at > 6 and > 9, respectively, compared to 76% identified by the SIMS. In Study 2, we recruited 100 patients and paired each with a healthy control and a fibromyalgia simulator (N = 300). Simulators scored highest on pseudosymptoms, while patients scored higher than controls. The SRSI-It identified 73% and 61% of simulators at cut scores of > 6 and > 9, compared to 51% and 34% of patients and 15% and 13% of controls. The SRSI-It demonstrated sensitivity to simulated pain, suggesting its utility in distinguishing simulators from honest respondents in clinical and forensic settings. However, caution is warranted to avoid misclassifying genuine patients, highlighting the need for complementary tools.