Depressive Symptomology and Gray Matter Integrity of Interoceptive Networks in Remitted Depressed Outpatients

Poster Session A - Saturday, April 13, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Liliana C. Wu¹ (liliana.wu@mail.utoronto.ca), Zindel V. Segal², Norman A. S. Farb^2,3; ¹University of Toronto, ²University of Toronto Scarborough, ³University of Toronto Mississauga

Introduction: Interoception, the sense of the body’s internal state, is increasingly recognized for its importance for mental health. Major Depression Disorder (MDD), while characterized by melancholia and anhedonia, is also marked by somatic comorbidities. Furthermore, MDD recurrence has been related to dysphoria-evoked inhibition of somatomotor regions, suggesting that interoceptive dysfunction may constitute an enduring biomarker of episode return. It remains unclear whether morphologic changes underlie these functional effects to help explain individual differences in MDD vulnerability. Method: A prior study (N=85) investigated the relationship between dysphoric reactivity and depression vulnerability over a two-year follow-up period. Here, we present secondary analysis of structural (T1) data not included in the original report. Gray matter volume was regressed onto future MDD status, residual symptom burden, and two composite measures of interoception: somatic anxiety (SomAnx) and lack of body awareness (Unaware). Whole brain and planned region of interest (ROI) analyses of sensory cortices were performed. Results: Future relapse/recurrence was not related to whole-brain gray matter volume. However, relapse was linked to greater cortical thickness in ROI analysis of interoceptive (insula) and visual (occipital) regions. Residual symptoms and SomAnx were linked to greater volume in the left inferior circular sulcus of the insula, and residual symptoms and Unaware were linked to greater volume in the right occipital pole. Conclusion: Residual symptoms and interoceptive dysfunction were associated with greater gray matter volume in sensory cortices. This contributes to a growing recognition of the relationship between depression vulnerability and sensory representation in relapse-remitted depressed outpatients.

Topic Area: EMOTION & SOCIAL: Emotion-cognition interactions