Minimal Impact of Sensation-Related Items on the Association Between Alexithymia and Self-Report Measures of Interoception.

Evidence suggests a relationship between alexithymia and self-report measures of interoception. As measures of alexithymia often include items that may pick up on interoceptive difficulty, however, it is possible that previously reported associations are driven by a lack of independence of measurement. Here, we explored the effect of removing sensation-related items from the Toronto Alexithymia Questionnaire (TAS-20) on the association between the TAS-20 and self-report measures of interoceptive accuracy (Studies 1 and 2; N = 330 and N = 476, respectively) and attention (Study 2). In both studies, removal of sensation-related items significantly reduced associations between the self-report measures of interoception and alexithymia. This effect was specific to the removal of sensation-related items (removing a random set of items did not result in a reduction in the size of the association). Importantly, relationships between alexithymia and self-reported interoception remained after item removal. Although effects were modest, it is recommended that future studies exploring relationships with self-report measures of interoception-particularly in relation to constructs where sensation-related items may broadly feature-should implement sensitivity analyses or employ alternative instruments that exclude sensation-related items, to ensure associations are not driven by a lack of independence of measurement.