In this article, the author will examine the structural and functional abnormalities exhibited in the brains of individuals diagnosed with borderline personality disorder. First, the amygdala, which is responsible for various processes involving emotion, tends to be hyper-active in those with borderline personality disorder. This is particularly the case when the borderline is experiencing suicidal feelings. It should therefore come as no surprise that the borderline tends to be emotionally highly volatile.
Thus, the borderline is in danger of overreacting to certain things. The amygdala is also responsible for emotional memories. It is important to keep this in mind when understanding the relation of borderline personality disorder to PTSD. Instead of merely registering certain affects with certain memories, the borderline may easily have traumatic memories triggered and replayed in their minds as though they were literally reliving the memories.
The prefrontal cortex of the borderline also exhibits certain structural abnormalities. This part of the brain is responsible for executive functions, which includes regulating social behavior in terms of what is socially appropriate or safe, mediating between good and bad choices in general, predicting the future results of current or past actions, and so on(Galen & Aguirre, 2013). In general, an underdeveloped prefrontal cortex tends to be associated with borderline personality disorder. In additional to this structural abnormality, the prefrontal cortex of the borderline individual simply exhibits less activity than those not diagnosed with the disorder. This is especially the case with borderlines who also suffer from PTSD(Galen & Aguirre, 2013). This is why they tend to engage in behavior which may appear to others as reckless or impulsive. In particular, the borderline tends to struggle with what is known as impulsive aggression:
In research, behaviors such as self-mutilation, physical violence, assault, destruction of property, and drug use fall under the category of impulsive aggression, which is the one area in BPD that is well researched. In one study of violent offenders and impulsive fire setters, 47 percent were found to have a personality-disorder diagnosis, in particular, borderline and antisocial personality disorders (Virkkunen et al. 1996 ). In another study , male perpetrators of domestic violence were more likely to have a diagnosis of BPD than men who did not engage in domestic violence (Dutton , Starzomski, and Ryan 1996) (Galen & Aguirre, 2013)
Some studies have associated borderline personality disorder with lower level of endogenous opioids. Their self-injuring behavior makes sense in light of this, since it can be understood as a means of experiencing endorphin euphoria, particularly when the endogenous opioids are so low as to create overwhelming negative emotions(Galen & Aguirre, 2013).
Those with BPD who self-injure, interestingly enough, report less physical pain when self-injuring, which is precisely the opposite of what one might expect. However, this is unsurprising when one considers that borderlines tend to injure during states of emotional hyper-arousal, when physical pain is less likely to be noticed by the individua(Galen & Aguirre, 2013)l. In addition to low endogenous opioids, some studies suggest that those with BPD have unusually low serotonin, which is likewise associated with suicidal behavior, self-injury, impulsive aggression, anxiety and depression; all of which afflict those with BPD to a disproportionate degree(Galen & Aguirre, 2013).
An intriguing experiment also shed some light on the interpersonal ramifications of borderline personality disorder. An fMRI was conducted on both healthy individuals and those with BPD as they played an economic game, in what the researchers believe may be the first time a distinct neurobiological signature for a personality disorder has been identified.
The “game” in which the subjects participated went like this: there were 55 healthy individuals and 55 individuals with BPD. The game involves an investor sending 20 dollars to a trustee. This triples the investment. The trustee divides this profit with the investor. The trustee determines how much he is going to give to the trustee. Thus, the trustee’s decision is instrumental in determining how much profit the investor receives.
All of the subjects had the fMRI scan their brains as they played. The anterior insula, a part of the brain known to be involved in activating when norms are violated, activated in healthy individuals in proportion to how how much money was sent and how much was received. In those with borderline personality disorder, however, the anterior insula activated only when they had to send money, but not when they were receiving it.
Some neurobiological studies have likewise found hypo-activity in parts of the frontal lobe having to do with inhibitory behavior, as well as hyperreactivity in parts o the brain having to do with negative emotionality, such as the amygdala:
Borderline personality disorder (BPD) is a severe mental disorder, characterized by pronounced deficits in emotion regulation, cognitive disturbances including dissociation, impulsivity, and interpersonal disturbances. Over the last decades, neuroimaging has become one of the most important methods to investigate neurobiological alterations possibly underlying core features of BPD. The aim of our article is to provide an overview of the latest neuroimaging research in BPD focusing on functional and structural MRI studies published since 2010. Findings of these studies are depicted and discussed referring to central domains of BPD psychopathology. On a neurochemical level, altered function in neurotransmitter systems including the serotonin, glutamate, and GABA systems was observed in patients with BPD. On a neural level, individuals with BPD showed structural and functional abnormalities in a fronto-limbic network including regions involved in emotion processing (e.g., amygdala, insula) and frontal brain regions implicated in regulatory control processes (e.g., anterior cingulate cortex, medial frontal cortex, orbitofrontal cortex, and dorsolateral prefrontal cortex). Limbic hyperreactivity and diminished recruitment of frontal brain regions may yield a link between disturbed emotion processing and other core features of BPD such as impulsivity and interpersonal disturbances. To clarify whether findings are specific to BPD, comparisons with other clinical groups are needed.
Baylor College of Medicine. (2008, August 11). A New Light On The Brains Of People With Borderline Personality Disorder. ScienceDaily. Retrieved December 7, 2014 from www.sciencedaily.com/releases/2008/08/080807144305.htm
Galen, Gillian; Aguirre, Blaise (2013-05-01). Mindfulness for Borderline Personality Disorder: Relieve Your Suffering Using the Core Skill of Dialectical Behavior Therapy (p. 39). New Harbinger Publications. Kindle Edition.