Personality Traits in Borderline Personality Disorder: A Cluster Analysis Based on the Millon Test Scores

INTRODUCTION: The complexity of the treatment of borderline personality disorder (BPD) is largely due to its heterogeneity. The aim of this study is to identify empirically derived patterns of co-occurring personality traits in individuals with primary BPD and to examine their clinical correlates. METHODS: Millon's personality traits (MCMI-IV) of 97 BPD patients were assessed and a cluster analysis of these traits was performed. Patients were evaluated on different clinical dimensions of BPD and compared between the different clusters found. RESULTS: Three trait-pattern clusters were obtained. Pattern 1 showed higher scores for borderline, histrionic, narcissistic and antisocial traits. Pattern 2 had higher scores for borderline, dependent and avoidant traits. Pattern 3 had lower levels of all the traits. Patients in patterns 1 and 2 showed greater scores on anxious-depressive scales. Pattern 1 also showed greater scores for anger expression. Pattern 3 patients were characterized for receiving more pharmacological treatment. CONCLUSIONS: Findings provide evidence for three patterns of co-occurring traits within BPD, consistent with dimensional conceptualizations and longstanding categorical overlap. These patterns align with externalizing-leaning, internalizing-leaning, and attenuated configurations and may help generate hypotheses for early characterization and treatment personalization.