Exploring Symptoms of Borderline Personality Disorder in People With Affective Disorders: A Network Analysis.

Objective: Borderline personality disorder (BPD) frequently co-occurs with affective disorders, such as major depressive disorder (MDD) and bipolar disorder (BD), yet the structure of BPD symptoms within these populations remains insufficiently characterized. This study utilizes network analysis to investigate the network structure of BPD symptoms in individuals with affective disorders. Methods: This study included 1323 participants: 783 individuals with affective disorders (MDD [n = 245], BD I [n = 120], BD II [n = 418]) and 540 controls without a history of psychiatric disorders. BPD symptoms were assessed using the Personality Assessment Inventory-Borderline Features Scale. A Gaussian graphical model was estimated using partial correlations among BPD symptoms, in which nodes correspond to individual symptoms and edges represent the relationships between them. Centrality analysis was subsequently conducted to compute strength, closeness, and betweenness centrality, providing insights into the relative importance and connectivity of individual symptoms within the network. Results: Analysis identified five distinct communities of BPD symptoms. The symptom "Feel empty" emerged as the most central trait across the affective disorder subgroups and the control group. Network comparison tests indicated no significant differences in network structure among the clinical subgroups, whereas a significant divergence was observed between the clinical and control groups. Conclusion: This study demonstrates that, although the symptom networks of BPD were largely comparable across affective disorder subgroups, structural differences emerged between the clinical and control groups. Notably, "Feel empty" consistently appeared as the most central symptom across all groups. These findings highlight the relevance of targeting "Feel empty" as a key focus for clinical intervention in affective disorders.