Interoception in obsessive-compulsive and major depressive disorders.

Atypical interoception is a transdiagnostic feature of psychiatric illness. Interoceptive alterations have been demonstrated in both obsessive-compulsive disorder (OCD) and major depressive disorder (MDD). However, the nature and direction of differences between patients and controls have been inconsistent, and interoception has not been directly compared between OCD and MDD in the same study. The current study addressed this gap by comparing OCD patients, MDD patients, and healthy controls (HCs) on three different facets of interoception: accuracy (IAcc; objective ability to detect bodily sensations), confidence in interoceptive ability (self-reported ability to detect bodily sensations accurately), and one dimension of interoceptive sensibility (IS; self-reported tendency to notice bodily sensation). Measures of IAcc and confidence were derived from responses in a heartbeat tracking task, whereas IS was measured with the Multidimensional Assessment of Interoceptive Awareness (MAIA) Noticing subscale. There were no differences between the groups in IAcc. Individuals with OCD displayed lower confidence in their interoceptive ability relative to both HC and MDD, although the pairwise effects did not survive multiple comparison-correction. Lower confidence was also nominally associated with greater obsessive-compulsive symptom severity. Both OCD patients and MDD patients exhibited significantly elevated IS compared to HCs, however, IS did not differ between patient groups. Exploratory analyses suggested a positive association between IAcc and confidence in interoceptive ability within OCD patients, while no associations between IAcc and confidence were found in MDD or HCs. These findings provide preliminary evidence for shared and potentially unique alterations of interoception in OCD and MDD.