Measuring Pain-related Behavioral Inhibition and Behavioral Activation System Responses: Further Validity Evidence for the Pain Responses Scale.

Objectives: The Pain Responses Scale and its Short Form (PRS-SF) were recently developed to assess the affective, behavioral, and cognitive responses to pain based on the behavioral inhibition system (BIS) and behavioral activation system (BAS) model of chronic pain. The purpose of this study was to provide additional tests of the psychometric properties of the PRS-SF in a new sample of individuals with chronic pain.

Methods: A sample of Spanish adults (N = 190) with chronic non-cancer pain completed a translated version of the PRS-SF and a battery of questionnaires measuring validity criteria hypothesized the be associated with BIS and BAS activation, including measures of sensitivity to punishment, sensitivity to reward, pain intensity, pain interference, catastrophizing, and pain acceptance.

Results: Confirmatory factor analysis supported a 4-factor structure for the PRS-SF assessing despondent, escape, approach, and relaxation responses (S-B χ 2 [5] = 1.49, Comparative Fit Index = 0.99, Non-Normed Fit Index = 0.99, root-mean-square error of approximation = 0.051, Akaike Information Criterion = 4113.66), with marginal internal consistency for 1 scale (relaxation) and adequate to good internal consistency for the others. The pattern of associations found between the PRS-SF Scale scores and the validity criterion supports the validity of the instrument.

Conclusion: The results provide additional support for the validity of the 4 PRS-SF Scale scores, and the reliability of 3 of the scales. If these findings are replicated in future research, investigators may wish to administer more items from the original Relaxation Scale when assessing this domain to ensure adequate reliability for this scale. The other items from the PRS-SF assessing despondent, escape, and approach responses appear to provide at least adequate reliability. When used in this way, the PRS-SF may be used to measure BIS and BAS responses to pain to: (1) provide further tests of the BIS-BAS model of chronic pain and/or (2) understand the potential mediating effects of BIS and BAS responses on the effects of psychological pain treatments to help determine which specific responses are most responsible for the benefits of treatment, and, therefore, which responses should be specifically targeted to enhance treatment response.