Somatization in patients with borderline personality disorder compared to healthy controls: The mediating roles of self‐ and other‐mentalizing in the effect of attachment insecurity

Abstract Aim Somatization is frequently observed in patients with borderline personality disorder (BPD). BPD is characterized by difficulties in mentalizing capacity. This study aimed to examine somatization in BPD patients compared with a healthy control group, focusing on the roles of self‐ and other‐mentalizing in the relationship between attachment insecurity and somatic symptoms. Method A total of 164 individuals, including 82 patients diagnosed with BPD and 82 healthy controls, participated in our study between August 2023 and March 2024. Somatization Scale, Experiences in Close Relationships‐Revised, Trait Meta‐Mood Scale, Mentalization Scale, Reading the Mind in the Eyes Test were used to assess somatization, dimensions of attachment insecurity, self‐ and other‐mentalizing. Moderated mediation analysis was conducted using Model 15 in the PROCESS macro added to SPSS. Results Somatization was observed to be more pronounced in patients with BPD compared to healthy controls. Self‐ and other‐mentalizing were closely related to somatization in BPD patients. It was demonstrated with moderated mediation analysis that clarity of feelings and mind‐reading ability mediated the association between attachment anxiety and somatization in BPD patients. In healthy controls, only clarity of feelings partially mediated this association. Conclusion Our findings suggest that self‐ and other‐mentalizing may serve as protective factors against the increased somatization observed in patients with BPD. Deficiencies in these mentalizing abilities may be linked to somatization due to difficulties in interpreting bodily signals and dealing with emotional distress from unstable relationships.