Additionally, women with BPD who reported a previous history of neglect by a female caregiver or abuse by a male caregiver were significantly more likely to have experienced sexual abuse by a non-caregiver.It has been suggested that children who experience chronic early maltreatment and attachment difficulties may go on to develop borderline personality disorder. Writing in the psychoanalytic tradition, Otto Kernberg argues that a childs failure to achieve the developmental task of psychic clarification of self and other and failure to overcome splitting might increase the risk of developing a borderline personality. Neurological patterns
The intensity and reactivity of a persons negative affectivity, or tendency to feel negative emotions, predicts BPD symptoms more strongly than does childhood sexual abuse. This finding, differences in brain structure (see Brain abnormalities), and the fact that some patients with BPD do not report a traumatic history suggest that BPD is distinct from the post-traumatic stress disorder which frequently accompanies it. Thus, researchers examine developmental causes in addition to childhood trauma. Research published in January 2013 by Anthony Ruocco at the University of Toronto has highlighted two patterns of brain activity that may underlie the dysregulation of emotion indicated in this disorder: (1) increased activity in the brain circuits responsible for the experience of heightened emotional pain, coupled with (2) reduced activation of the brain circuits that normally regulate or suppress these generated painful emotions.
These two neural networks are seen to be dysfunctionally operative in the limbic system, but the specific regions vary widely in individuals, which calls for the analysis of more neuroimaging studies.Also (contrary to the results of earlier studies) those with BPD showed less activation in the amygdala in situations of increased negative emotionality than the control group. John Krystal, editor of the journal Biological Psychiatry, wrote that these results "[added] to the impression that people with borderline personality disorder are set-up by their brains to have stormy emotional lives, although not necessarily unhappy or unproductive lives". Their emotional instability has been found to correlate with differences in several brain regions. Mediating and moderating factors
Executive function
While high rejection sensitivity is associated with stronger symptoms of borderline personality disorder, executive function appears to mediate the relationship between rejection sensitivity and BPD symptoms. That is, a group of cognitive processes that include planning, working memory, attention, and problem-solving might be the mechanism through which rejection sensitivity impacts BPD symptoms. A 2008 study found that the relationship between a persons rejection sensitivity and BPD symptoms was stronger when executive function was lower and that the relationship was weaker when executive function was higher. This suggests that high executive function might help protect people with high rejection sensitivity against symptoms of BPD. A 2012 study found that problems in working memory might contribute to greater impulsivity in people with BPD. Family environment
Family environment mediates the effect of child sexual abuse on the development of BPD.