A Bifactor Analysis of the 20-Item Toronto Alexithymia Scale: Further Support for a General Alexithymia Factor

The 20-Item Toronto Alexithymia Scale (TAS-20) is the most widely used measure to assess the personality construct of alexithymia and is composed of three-factor analytically derived subscales. These subscales measure and represent three critical, theoretically based facets of alexithymia. The subscales are distinct, yet highly interrelated and only as a collective body do they reflect adequately the alexithymia construct. Although different studies using both university student and community samples suggest that TAS-20 total scores are largely reflective of variation on a single construct, and that subscale scores do not provide unique and reliable information beyond total scores, many users of the scale frequently continue to employ and even rely more heavily on subscale scores rather than total scale scores when interpreting research study outcomes. Our goal in this study is to provide clinicians and researchers with replicable psychometric information for the TAS-20 estimated from bifactor modeling in an attempt to provide further support for using total rather than subscale scores. In general, our findings were consistent with previous studies indicating that TAS-20 total scores can be considered indicative of a single construct. The replication of these earlier results from previous investigations provides additional support for the use of a total TAS-20 score and questions the utility of using TAS-20 subscale scores. Based on these results, we recommend that researchers and clinicians use a single total TAS-20 score and not subscale scores.