Accordingly, he considered trauma to be one of many stressors that could worsen the already-impaired "mental deficiency" of a hysteric, thereby generating a cascade of hysterical (in todays language, "dissociative") symptoms.Although there was great interest in dissociation during the last two decades of the nineteenth century (especially in France and England), this interest rapidly waned with the coming of the new century. Even Janet largely turned his attention to other matters. There was a sharp peak in interest in dissociation in America from 1890 to 1910, especially in Boston as reflected in the work of William James, Boris Sidis, Morton Prince, and William McDougall. Nevertheless, even in America, interest in dissociation rapidly succumbed to the surging academic interest in psychoanalysis and behaviorism. For most of the twentieth century, there was little interest in dissociation. Despite this, a review of 76 previously published cases from the 1790s to 1942 was published in 1944, describing clinical phenomena consistent with that seen by Janet and by therapists today. In 1971, Bowers and her colleagues presented a detailed, and still quite valid, treatment article. The authors of this article included leading thinkers of their time – John G. Watkins (who developed ego-state therapy) and Zygmunt A. Piotrowski (famed for his work on the Rorschach test). Further interest in dissociation was evoked when Ernest Hilgard (1977) published his neodissociation theory in the 1970s.
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.