Development of Cut-Scores for Feigning Spectrum Behavior on the Orebro Musculoskeletal Pain Screening Questionnaire and the Perceived Stress Scale: A Simulation Study

Background/Objectives: Feigning spectrum behavior (FSB) is the exaggeration, fabrication, or false imputation of symptoms. It occurs in compensable injury with great cost to society by way of loss of productivity and excessive costs. The aim of this study is to identify feigning by developing cut-scores on the long and short forms (SF) of the Orebro Musculoskeletal Pain Screening Questionnaire (OMPSQ and OMPSQ-SF) and the perceived Stress Scale (PSS and PSS-4). Methods: As part of pre-screening for a support program, 40-injured workers who had been certified unfit for work for more than 2-weeks were screened once with the OMPSQ and PSS by telephone by a mental health professional by telephone. A control sample comprised of 40-non-injured community members were screened by a mental health professional on four occasions under different aliases, twice responding genuinely and twice simulating an injury. Results: Differences between the workplace injured people and the community sample were compared using ANCOVA with age and gender as covariates, and then Receiver Operator Characteristics (ROC) were calculated. The OMPSQ and OMPSQ-SF discriminated (ρ < 0.001) between all conditions. All measures discriminated between the simulation condition and workplace injured people (ρ < 0.001). Intraclass correlation demonstrated the PSS, PSS-4, OMPSQ and OMPSQ-SF were reliable (ρ < 0.001). Area Under the Curve (AUC) was 0.750 for OMPSQ and 0.835 for OMPSQ-SF for work-injured versus simulators. Conclusions: The measures discriminated between injured and non-injured people, and non-injured people instructed to simulate injury. Non-injured simulators produced similar scores when they had multiple exposures to the test materials, showing the uniformity of feigning spectrum behaviour on these measures. The OMPSQ-SF has adequate discriminant validity and sensitivity to feigning spectrum behaviour, making it optimal for telephone screening in clinical practice.