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Borderline Personality Disorder and Posttraumatic Stress Disorder: Unique Patterns of Emotion Reactivity and Regulation

Both borderline personality disorder (BPD) and posttraumatic stress disorder (PTSD) are associated with emotion dysfunction and often co-occur. Emotional reactivity is also evident in some studies in BPD and PTSD. Despite the frequent co-occurrence of these diagnoses, only a few studies have examined the independent and joint effects of BPD and PTSD on emotional functioning. Some data suggest that co-occurring PTSD may drive discordance between domains of emotional reactivity in BPD, dampening physiological reactivity but increasing subjective reactivity. Low reliance on acceptance-based emotion regulation may also account for this divergence. The current study examined the independent and interactive effects of BPD and PTSD on emotional reactivity, regulation, and concordance across physiological and subjective measures. We also examined the role of acceptance in driving concordance across physiological and subjective measures. Participants (N = 195) underwent a diagnostic interview and completed a computerized task including neutral and negative emotion inductions. We examined subjective and physiological outcomes after both inductions. Linear regressions were used to examine relationships between diagnostic group and self-reported reactivity and regulation outcomes, as well the mediating role of acceptance on discordance. Multilevel models were used to examine the associations between diagnostic criteria and time on reactivity and regulation outcomes. We found that BPD and BPDxPTSD, but not PTSD, were significantly associated with greater difficulty regulating and accepting emotions. No significant differences in physiological reactivity and regulation were present across diagnostic groups, and acceptance was not found as a mediator between diagnostic groups and discordance indices. We discuss possible interpretations of our reactivity and regulation findings. Investigating BPD and PTSD’s association with reactivity and regulation, along with the role of emotional acceptance on these outcomes, will extend our understanding of diagnostic profiles and potentially pinpoint how acceptance can be utilized to influence emotional concordance.