Common and distinct structural network abnormalities in major depressive disorder and borderline personality disorder.

Major depressive disorder (MDD) and borderline personality disorder (BPD) show substantial overlap in both affective symptom expression and in regional brain volume reduction. To address the specificity of structural brain change for the respective diagnostic category, we investigated structural networks in MDD and BPD to identify shared and distinct patterns of abnormal brain volume associated with these phenotypically related disorders. Using magnetic resonance imaging at 3 T, we studied 22 females with MDD, 17 females with BPD and without comorbid posttraumatic stress disorder, and 22 age-matched female healthy controls. We used “source-based morphometry” (SBM) to investigate naturally grouping patterns of gray matter volume variation (i.e. “structural networks”) and the magnitude of their expression between groups. SBM identified three distinct structural networks which showed a significant group effect (p b 0.05, FDR-corrected). A bilateral frontostriatal network showed reduced volume in MDD compared to both controls and BPD patients. A medial temporal/medial frontal network was found to be significantly reduced in BPD compared to both controls and MDD patients. Decreased cingulate and lateral prefrontal volume was found in both MDD and BPD when compared to healthy individuals. In MDD significant relationships were found between depressive symptoms and a cingulate/lateral prefrontal structural pattern. In contrast, overall BPD symptoms and impulsivity scores were significantly associated with medial temporal/medial frontal network volume. The data suggest both distinct and common patterns of abnormal brain volume in MDD and BPD. Alterations of distinct structural networks differentially modulate clinical symptom expression in these disorders.