Diffusion Tensor Anisotropy in the Cingulum in Borderline and Schizotypal Personality Disorder

Abstract

Borderline personality disorder (BPD) and schizotypal personality disorder (SPD) are both characterized by inflexible and pervasive behavioral patterns that frequently lead to significant functional impairment. Although considerable research has been conducted on the biological and phenotypic aspects of these disorders, researching, diagnosing, and treating them remains a challenge, primarily due to the difficulties associated with the categorical nature of current diagnostic methods (Skodol and Bender, 2009) which, in turn, results in significant within-group heterogeneity and between-group co-occurrence. Given the relative paucity of research comparing aspects of these disorders with one another, the current study aimed to evaluate overlapping and differentiating aspects of BPD and SPD by examining the integrity of a brain region frequently implicated in both disorders, the cingulum. The current study used a 3T Siemens scanner to acquire structural and diffusion tensor imaging in age-, sex-, and education-matched groups of 28 adults with BPD, 32 adults with SPD, and 36 healthy control participants (HC). The anterior and posterior cingulate were manually traced on all participants and then volume and fractional anisotropy (FA) comparisons were conducted across the groups for the left and right anterior and posterior cingulate. Compared with HC, SPD patients had smaller relative cingulate white matter volume and BPD patients had marginally significantly smaller relative cingulate white matter volume, and the two patient groups did not differ from one another. With regard to FA findings, a spectrum pattern emerged, such that the BPD group had significantly lower FA in the posterior cingulum relative to controls, whereas the SPD group also had lower FA in this region but did not differ from HC. The BPD group had marginally lower FA in dorsal aspects of the anterior cingulum when compared with HC, and the SPD patients did not differ from HC or BPD individuals. In summary, the current study provides evidence of aberrant connectivity of the cingulum in BPD patients, but not SPD patients, compared with HC individuals. Consistent with prior work, overall results suggest potential involvement of cingulum in BPD symptomatology.