(PS3-A16) A General Factor of Self-reported Interoception Moderates the Effects of Depression Level on Somatic Symptoms

Introduction:  Depression is often experienced with somatic complaints and involves physiological changes. Therefore, there has been a robust increase in the study of depression within the framework of interoception (i.e., the perception and interpretation of bodily signals). Recently, a self-report questionnaire, the Multidimensional Assessment of Interoceptive Awareness (MAIA), has shown consistent results that higher depression is related to lower interoceptive awareness, and MAIA scores have even demonstrated a dose-response relationship to antidepressive treatment, further highlighting the interconnected nature of depression and interoception. The current study sought to build on this work by examining interoception as a moderator of the link between depressive symptoms and somatic symptoms. Thus, we hypothesized that self-reported interoception will serve as a protective factor, weakening the link between depressive symptoms and somatic symptoms.

Methods:  A sample of 2,028 online respondents (75% women, 84% Caucasian, Mage = 47 years old, 9% high school educations or less) completed the 9-item Patient Health Questionnaire (PHQ-9), the 15-item Patient Health Questionnaire (PHQ-15), and Multidimensional Assessment of Interoceptive Awareness, Version 2 (MAIA-2) within a 40-minute cross-sectional online survey. Confirmatory factor analysis (CFA) and the latent moderated structural equation (LMS) were conducted to extract a factor and investigate moderation as hypothesized.

Results:  Analyses replicated that higher depression was related to more severe somatic symptoms and lower interoceptive awareness. Contrary to our hypothesis, the links between depressive symptoms and somatic symptoms became stronger when the self-reported interoception was higher, suggesting that interoceptive awareness might predispose individuals toward conflating emotional and physical discomfort.

Conclusions:  The biggest limitation of this study is that the inference of causality is limited due to the cross-sectional nature of the data. Future studies are encouraged to investigate this in a longitudinal study and in a clinical population to explore directions of causality. Despite these limitations, the findings were supportive of a general latent factor in self-reported interoceptive characteristics such as the g factor in intelligence. Also, it illuminates how interoceptive awareness might interact with depressive symptoms to shape the experiencing of physical symptoms within a big community sample.