Brain structural anomalies in borderline and avoidant personality disorder patients and their associations with disorder-specific symptoms

- We investigate structural brain volumes in personality disorder patients.
- Borderline patients show relatively reduced medial prefrontal cortex (MPFC) volume.
- Borderline and avoidant patients show positive amygdala volume-anxiety correlations.
- Healthy controls but not patients show a negative MPFC volume-anxiety correlation.
- The results suggest potentially compensatory aspects of structural brain volume.

BackgroundBorderline personality disorder (BPD) and avoidant personality disorder (AvPD) are characterized by hyper-reactivity to negatively-perceived interpersonal cues, yet they differ in degree of affective instability. Recent work has begun to elucidate the neural (structural and functional) and cognitive-behavioral underpinnings of BPD, although some initial studies of brain structure have reached divergent conclusions. AvPD, however, has been almost unexamined in the cognitive neuroscience literature.MethodsIn the present study we investigated group differences among 29 BPD patients, 27 AvPD patients, and 29 healthy controls (HC) in structural brain volumes using voxel-based morphometry (VBM) in five anatomically-defined regions of interest: amygdala, hippocampus, medial prefrontal cortex (MPFC), dorsolateral prefrontal cortex (DLPFC), and anterior cingulate cortex (ACC). We also examined the relationship between individual differences in brain structure and self-reported anxiety and affective instability in each group.ResultsWe observed reductions in MPFC and ACC volume in BPD relative to HC, with no significant difference among patient groups. No group differences in amygdala volume were found. However, BPD and AvPD patients each showed a positive relationship between right amygdala volume and state-related anxiety. By contrast, in HC there was an inverse relationship between MPFC volume and state and trait-related anxiety as well as between bilateral DLPFC volume and affective instability.LimitationsCurrent sample sizes did not permit examination of gender effects upon structure-symptom correlations.ConclusionsThese results shed light on potentially protective, or compensatory, aspects of brain structure in these populations-namely, relatively reduced amygdala volume or relatively enhanced MPFC and DLPFC volume.