Examining the Incremental Validity of the Perth Alexithymia Questionnaire (PAQ) Relative to the 20-Item Toronto Alexithymia Scale (TAS-20)

Abstract

The 20-item Toronto Alexithymia Scale (TAS-20) is the most widely used instrument for assessing alexithymia, with more than 25 years of research supporting its reliability and validity. The items that compose this scale were written to operationalize the components of the construct that are based on clinical observations of patients and thought to reflect deficits in the cognitive processing of emotions. The Perth Alexithymia Questionnaire (PAQ) is a recently introduced measure and is based on a theoretical attention-appraisal model of alexithymia. An important step with any newly developed measure is to evaluate whether it demonstrates incremental validity over existing measures. In this study using a community sample (N = 759), a series of hierarchical regression analyses were conducted that included an array of measures assessing constructs closely associated with alexithymia. Overall, the TAS-20 showed strong associations with these various constructs to which the PAQ was unable to add any meaningful increase in prediction relative to the TAS-20. We conclude that until future studies with clinical samples using several different criterion variables demonstrate incremental validity of the PAQ, the TAS-20 should remain the self-report measure of choice for clinicians and researchers assessing alexithymia, albeit as part of a multi-method approach.

Statement of ethics

This study protocol was reviewed and approved by the University of Toronto Research Ethics Board (Protocol #41341).

Informed consent to participate in this study was obtained from each participant prior to any data collection.

Declaration of interest

None of the authors have any conflicts of interest to disclose.

Author contributions

All authors have contributed to all aspects of the manuscript and approved the final manuscript.

Data availability statement

The data is currently unavailable online. Data may become available upon reasonable request to the corresponding author.

Notes

1 Preece et al. (Chan et al., 2022) similarly point out that the TAS-20 and the PAQ “are based on slightly different theoretical models that vary subtly in their definitions of EOT . . . The TAS-20 model considers EOT to reflect a tendency to not focus on feelings or thoughts . . . whereas the PAQ model considers it a tendency to not focus internally on feelings (Preece et al., 2017)” (p. 14). They are correct that “the TAS-20 has a broader conceptualization of EOT that is not just specific to emotions, but cognitive styles or thought content more broadly” (p. 14), which in our view includes an absence or paucity of fantasies, and is therefore more faithful to the concept of pensée opératoire which Nemiah et al. (1976) described as an essential component of alexithymia.

2 The Toronto Structured Interview for Alexithymia (Bagby et al., 2006) was developed for this purpose and has been translated and validated in Dutch, German, and Italian versions.

3 The IMMB subscale of the PMS and the EA subscale of the MAIA-2 were not included in the regression models due to their violation of one or more linear regression assumption (see Results section below).

Additional information

Funding

Data collection for this study was supported by internal funding at the University of Toronto.