Background: This article reports three studies describing the development and validation of the 12-item Sensitivity to Pain Traumatization Scale (SPTS-12). SPT refers to the anxiety-related cognitive, emotional, and behavioral reactions to pain that resemble the features of a traumatic stress reaction.
Methods: In Study 1, a preliminary set of 79 items was administered to 116 participants. The data were analyzed by using combined nonparametric and parametric item response theory resulting in a 12-item scale with a one-factor structure and good preliminary psychometric properties. Studies 2 and 3 assessed the factor structure and psychometric properties of the SPTS-12 in a community sample of 823 participants (268 with chronic pain and 555 pain-free) and a clinical sample of 345 patients (126 with chronic post-surgical pain, 92 with other nonsurgical chronic pain, and 127 with no chronic pain) at least 6 months after undergoing coronary artery bypass graft surgery, respectively.
Results: The final SPTS-12 derived from Study 1 comprised 12 items that discriminated between individuals with different levels of SPT, with the overall scale showing good to very good reliability and validity. The results from Studies 2 and 3 revealed a one-factor structure for chronic pain and pain-free samples, excellent reliability and concurrent validity, and moderate convergent and discriminant validity.
Conclusion: The results of the three studies provide preliminary evidence for the validity and reliability of the SPTS-12.
Keywords: chronic pain; chronic post-surgical pain; factor analysis; item response theory analysis; measurement; psychology; scale development; trauma.