From early relational experiences to non-suicidal self-injury in anorexia and bulimia nervosa: a structural equation model unraveling the role of impairments in interoception

Purpose: Individuals with anorexia nervosa (AN) and bulimia nervosa (BN) frequently exhibit Non-Suicidal Self-Injury (NSSI), yet their co-occurrence is still unclear. To address this issue, the aim of this study was to elucidate the role of impairments in interoception in explaining the NSSI phenomenon in AN and BN, providing an explanatory model that considers distal (insecure attachment/IA and traumatic childhood experiences/TCEs) and proximal (dissociation and emotional dysregulation) risk factors for NSSI. Method: 130 patients with AN and BN were enrolled and administered self-report questionnaires to assess the intensity of NSSI behaviors, interoceptive deficits, IA, TCEs, emotional dysregulation and dissociative symptoms. Results: Results from structural equation modeling revealed that impairments in interoception acted as crucial mediators between early negative relational experiences and factors that contribute to NSSI in AN and BN, particularly emotional dysregulation and dissociation. Precisely, both aspects of IA (anxiety and avoidance) and various forms of TCEs significantly exacerbated interoceptive deficits, which in turn are associated to the emergence of NSSI behaviors through the increase in levels of dissociation and emotional dysregulation. Conclusions: The proposed model provided a novel explanation of the occurrence of NSSIs in patients with AN and BN by accounting for the significance of interoception.