The Impact of Emotional Distress on Cognitive Performance in Borderline Personality Disorder

Individuals with borderline personality disorder (BPD) are prone to intense emotional reactions and dysfunctional interpersonal relationships, which may be associated with disruptions in cognitive functioning. However, research comparing neurocognitive functioning in BPD compared to patients with comorbid disorders like MDD and healthy control groups has been inconclusive. This study was the first to directly measure BPD individuals' working memory capacities under stressful conditions, using an experimentally manipulated, in-vivo social stressor. The primary aims of this study were to investigate the impact of emotional distress on working memory performance in the context of a psychological stress procedure (Trier Social Stress Test) and to determine whether emotion-induced working memory disruption was stronger for participants with BPD (n = 60) than for participants with MDD (n = 30) or healthy controls (n = 21). Results showed that emotional distress positively predicted working memory errors in the sample overall, with self-reported feelings of confusion and vigor accounting for this relationship. However, there were no basic working memory differences between BPD participants, MDD participants, and controls. BPD participants were also not more likely to have impairments in working memory as a consequence of emotional distress compared to participants with MDD. Participants with BPD were more likely to have had a history of self-injurious behavior, showed poorer psychosocial functioning, and showed higher levels of depression, anxiety, aggression, and impulsivity. When the effects of emotional distress were controlled for, participants with BPD were shown to have superior working memory performance, while MDD participants were shown to have poorer working memory performance, compared to the sample mean. Findings from the current study underscore the need to account for emotional distress when examining working memory in BPD and MDD groups. Mood fluctuations and emotional reactivity may play a larger role than pathophysiological factors in characterizing neurocognitive performance in these groups. These findings could point to a deficit in MDD, perhaps characterized by insufficient reactivity to the mobilizing effects of mild stress. Alternatively, BPD individuals' greater attunement and sensitivity to others' emotional states may paradoxically confer an advantage when pure attentiveness and concentration are called for. Future research should aim to identify psychological and neurocognitive strengths among individuals with BPD. Given the equivocal and complex findings on neurocognitive performance in BPD to date, more research is needed to develop a clear profile.