Attachment and Borderline Personality Disorder: Differential Effects on Situational Socio-Affective Processes.

Insecure attachment and borderline personality disorder (BPD) are defined by similar affective and interpersonal processes. Individuals diagnosed with BPD, however, represent only a subset of those described as insecurely attached, suggesting that attachment may hold broader relevance for socio-affective functioning. Based on a 21-day ecological momentary assessment protocol in a mixed clinical and community sample ( = 207) oversampled for BPD, we evaluate the discriminant validity of each construct as it influences daily interpersonal interactions. We find that insecure attachment is associated with elevated perceptions of interpersonal disaffiliation and maladaptive strategies for affect regulation, whereas enacted interpersonal hostility is more distinctive for BPD. In a series of sensitivity analyses, we further highlight potential caveats to these findings when studying both constructs concurrently. Together, our results suggest that both insecure attachment and BPD contribute to problematic affective and interpersonal processes, but that they do so at different stages of the unfolding social interaction, which has important implications for their maintenance and treatment.