Atypical Neural Plasticity and Behavioral Effects of Trustworthiness Learning in High Vs. Low Borderline Personality Disorder Features: An Experimental Approach

Background: The ability to accurately decide who is trustworthy, and to, in the face of new information, adjust judgment of others’ trustworthiness accurately, flexibly, and efficiently is clinically impaired in Borderline Personality Disorder (BPD). Methods: A novel trust learning paradigm was administered to high (H-BPD) and low (L-BPD) in BPD features undergraduate participants. Neutral faces were paired with trust-relevant behaviors in each of four conditions: trustworthy, untrustworthy, mixed, and ambiguous. After training, participants rated faces on trustworthiness as electroencephalographic measures were recorded. Results: H-BPD rated neutral faces as significantly more untrustworthy than L-BPD at both time periods. Negative and ambiguous trustworthiness pairing conditions led to lower trustworthiness ratings, whereas trustworthy and mixed descriptors led to higher trustworthiness ratings. Training enhanced the amplitude of an early sensory ERP component (i.e., P1) for both groups. The slow wave ERP, an index of sustained attention, revealed greater focus after training to trustworthy descriptors in H-BPD and to untrustworthy descriptors in L-BPD. Conclusions: Social learning can modify an untrustworthiness bias in BPD at neural and behavioral levels. The results suggest that differential neural plasticity may account for the negative trustworthiness appraisal bias in BPD, and that interventions targeting frontal, attentional processes during trustworthiness learning may be a key mechanism of therapeutic change.