Supplementary Material for: Antagonistic narcissism in women with Borderline Personality Disorder: a case control study

Objective: BPD is characterized by instability in self-image, emotions, and relationships. Features such as (auto)aggression, devaluation and impulsivity indicate proximity to narcissistic traits, especially antagonistic aspects. While its links to grandiose and vulnerable narcissism are established, the role of antagonistic narcissism (AN) remains unclear. This study investigates AN in BPD by comparing female BPD patients with a diagnostically heterogeneous clinical control group without personality disorders and by examining its associations with symptom severity, self-harm, aggression, interpersonal problems and empathy. Methods: 51 female BPD patients and 51 clinical control patients completed the Narcissistic Admiration and Rivalry Questionnaire (NARQ) and measures of borderline symptomatology, aggression, interpersonal problems, and empathy. Group comparisons were conducted using analyses of covariance, and Spearman correlations examined relationships between clinical characteristics. Interpersonal tendencies of AN were analyzed via the Structural Summary Method (SSM). Results: BPD patients showed higher levels of AN compared to the control group (η² = 0.04), though this difference was only marginally significant (p = 0.050). AN correlated positively with overall aggression (r = .34, p < .05), particularly verbal aggression (r = .43, p < .01). SSM analysis positioned AN within the domineering-vindictive quadrant of the Interpersonal Circumplex, characterized by high dominance and low affiliation. No significant correlation was found with empathy. Conclusion: Findings suggest a potential elevation of AN in females with BPD and its associations with aggression and interpersonal dysfunction, highlighting the complexity of narcissistic traits in BPD and the need for further research.