Assessing alexithymia in chronic pain: psychometric properties of the Toronto Alexithymia Scale-20 and Perth Alexithymia Questionnaire.

Introduction: Alexithymia is elevated in chronic pain and relates to poor pain-related outcomes. However, despite concerns from other clinical populations, the psychometric properties of alexithymia measures have not been rigorously established in chronic pain. Objective: This study examined the psychometric properties of the Toronto Alexithymia Scale-20 Item (TAS-20) and the Perth Alexithymia Questionnaire (PAQ) in adults with chronic pain. Methods: An online sample of adults with chronic pain across the United States (N = 1453) completed the TAS-20, PAQ, and related questionnaires at baseline, 3-month follow-up, and 12-month follow-up. Results: Both measures showed good temporal stability, convergent validity (with emotion regulation scores), divergent validity (with depression and anxiety scores), and criterion validity. Some concerns were raised about the TAS-20: the original 3-factor structure showed a poor model fit; the Externally Oriented Thinking subscale of the TAS-20 had poor factor loadings and unacceptable internal consistency; and, we identified several TAS-20 items that may slightly inflate the predictive validity of the TAS-20 on pain-related outcomes. The original 5-factor structure of the PAQ showed a good fit; each PAQ subscale had good factor loadings and excellent internal consistency. Conclusions: Both the TAS-20 and PAQ had psychometric strengths. Our data raised some concern for the use of TAS-20 subscales; the PAQ may be a psychometrically stronger option, particularly for investigators interested in alexithymia subscale analysis in people with chronic pain.