Interoceptive sensibility mediates emotional dysregulation: Insights from individuals with Bipolar II Depression

Emotion dysregulation (ED), a core feature of Bipolar Disorder (BD), contributes to symptom severity, mood instability, and reduced quality of life. Emerging evidence suggests that interoception-the ability to perceive and integrate internal bodily signals-may play a pivotal role in shaping emotional experience. However, the relationship between interoceptive sensibility and ED in BD remains poorly understood. This study investigated whether interoceptive sensibility mediates ED in individuals with Bipolar II Disorder during a depressive episode (BD2-D). Sixty inpatients with BD2-D and 36 healthy controls completed a psychometric assessment including the Difficulties in Emotion Regulation Scale (DERS), the Multidimensional Assessment of Interoceptive Awareness (MAIA), the Beck Depression Inventory-II (BDI-II), and the Self-Rating Anxiety Scale (SAS). Compared to controls, patients exhibited significantly higher ED across all DERS components (p-value <0.01), and lower interoceptive sensibility, both in total scores and in six of eight MAIA components (p < 0.005). Partial correlations showed strong negative associations between interoceptive sensibility and ED, particularly in self-regulation and trust in bodily signals. Mediation analysis indicated that interoceptive sensibility significantly mediated the relationship between BD2-D and ED (indirect effect β = 16.18, 95 % CI [8.54, 27.54]). These findings highlight the pivotal role of interoceptive sensibility in emotional regulation in BD2-D. Impaired integration of bodily signals may jeopardize self-regulation and increase emotional vulnerability. Interoception may therefore represent a promising target for intervention in mood disorders.