Depression May Not Be Related to Impaired Interoceptive Sensibility: The Role of Alexithymia

Interoceptive impairments are increasingly recognized as psychopathology processes underlying emotional disorders. However, their relationship with depression remains inconclusive. Alexithymia may influence the association between interoception and depressive symptoms. This study aimed to examine the role of alexithymia between interoception and depression. Eighty-eight depressed patients (DEPs) and fifty healthy controls (HCs) were recruited. Interoceptive sensibility was assessed using the Multidimensional Assessment of Interoceptive Awareness, and interoceptive accuracy and interoceptive awareness were evaluated through heartbeat counting tasks. Alexithymia was measured with the Toronto Alexithymia Scale. In the DEP group, depressive symptoms were assessed using the Hamilton Depression Scale. In DEPs, none of the three dimensions of interoception were associated with depressive symptoms. The alexithymic depressed patients exhibited lower interoceptive sensibility than their non-alexithymic counterparts, while the latter did not differ from the HC group. Moreover, alexithymia mediated the link between interoceptive sensibility and depressive symptoms. These results suggested that impaired interoceptive sensibility may primarily contribute to alexithymia, which, in turn, leads to depression. This highlights the importance of addressing alexithymia in therapeutic interventions aimed at improving the interoceptive process in depressed individuals.