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Your Brain on Trauma: Looking at Borderline Personality Disorder from a Trauma Perspective

Updated: Mar 13




Trauma is a fickle thing. It is highly nuanced and difficult to predict how it will affect an individual. It can also be difficult to agree upon what counts as legitimate trauma as each person responds to distressful experiences differently.


What is interesting about trauma is how it actually affects parts of the brain and can change the way the brain operates. The fact that trauma can change your brain may make the idea of healing sound daunting and like a hopeless endeavor. However, there is good news: while trauma changes the brain, healing also changes the brain. Neuroplasticity speaks to the beautiful and weird ways our brains can change and heal after trauma.


Wikipedia describes neuroplasticity this way: Neuroplasticity, also known as neural plasticity, or brain plasticity, is the ability of neural networks in the brain to change through growth and reorganization. It is when the brain is rewired to function in some way that differs from how it previously functioned. These changes range from individual neuron pathways making new connections, to systematic adjustments like cortical remapping. Examples of neuroplasticity include circuit and network changes that result from learning a new ability, environmental influences, practice, and psychological stress.


Trauma affects more than just your behavior and your emotions; it also affects your body. This happens because trauma changes the way your brain works. There are many parts of the brain that are affected by trauma but the parts that seem to be the most activated during and after a traumatic event are the hippocampus and the amygdala.


The amygdala is known as the “fear center” of the brain. This little almond-shaped part of the brain is the part that activates your fear response and determines whether or not something is a threat or a danger to you. This part relies on the hippocampus to inform it of whether or not something is a threat.


The hippocampus does this because it acts as the memory center of the brain. It works as a time stamp by allowing us to understand past events as things that happened in the past and not something that is actually happening in the present. The hippocampus also provides information based on past experiences to the amygdala about whether there is a threat present.





For people with PTSD, this area of the brain is often smaller and less active. When the hippocampus is not functioning properly, it may provide inaccurate information to the amygdala by telling it that something is a threat when in fact it is not. This may play a role in flashbacks that people with PTSD often experience. It may also play a role in the exaggerated startle responses that many people with PTSD have.


In the context of borderline personality disorder, it may shed light on how the traumatized brain plays a role in the behavior of people with BPD. BPD carries much stigma and people with BPD are often viewed negatively, by both mental health professionals and people who are not in the mental health field.


However, some people in the mental health field are starting to recognize it as an attachment trauma-related disorder. Personality disorder or not, when you think of people with BPD from the trauma perspective, it may help us understand the behavior that people with BPD exhibit, particularly how they behave with others in their interpersonal relationships.


Many of the symptoms of BPD are similar to trauma: substance use, self-harm, and dissociation are some of the more commonly known signs of BPD or borderline behavior. It is not uncommon for people with BPD to struggle in their relationships with others. People with BPD can be known to do something referred to as “splitting.” In relationships, this looks like idealizing someone only to devalue them when and if the person does something to upset the person with BPD.


The person will fall from friend to foe status in that moment. It also looks like viewing things and situation as all good or all bad or as always working out or never working out. People with BPD can struggle to hold two opposite truths together at once.





For example, a person with BPD may react strongly to a loved one in an argument or when there has been a perceived slight. They may not be capable of holding their love for the person together with the anger and hurt feelings they have towards the person in that moment. People with BPD may often live in an all or nothing world.


It is interesting to see how BPD looks when we apply information about the hippocampus and the amygdala to this behavior. Let’s say a person who has BPD grew up with a caregiver who was abusive or emotionally unavailable (remember- the newer school of thought around BPD is that it is related to attachment trauma).


More than likely the person with BPD was emotionally abused, neglected, and devalued. The person probably felt they had to separate from their true self in order to survive. They may have found themselves on a constant, never-ending hamster wheel trying to chase the love and acceptance of this caregiver, never realizing that they were in a no-win situation.


This dynamic often feels like it will never end and can follow the person into adulthood. A person with BPD, who more than likely experienced attachment trauma, may have a traumatized brain.


If someone hurts them, whether on purpose or not, their hippocampus may be providing the amygdala false information about the person and therefor sends information to the amygdala that the person is a threat, rather than an otherwise trustworthy person who made a mistake.


Attachment trauma can make it extremely difficult to differentiate between the actual toxic offenders from the loved ones who made a human error. If your hippocampus is telling your amygdala that your spouse or best friend is a threat and intends to harm you when they don’t intend harm at all, you will more than likely enter fight or flight mode.


That person has now become an enemy that you must fight to defend yourself from, or flee from, even if they realistically pose no real threat to you and your safety. This type of misperception can lead to lashing out and splitting. This is where people who struggle with BPD find their relationships struggling.





I want to be clear that this is simply a theory I have and it is not supported by any empirical research (that I know of). It is simply my own observations made over the course of the last ten years working with trauma survivors.


It has been interesting to see how many of my patients respond when I explain how their brains can sometimes lie to them, especially when their brains are operating on trauma mode. It has also been interesting and inspiring to see how they begin to make subtle changes in their lives and relationships once they begin to view the world from this perspective.


While Dialectical Behavioral Therapy is the most popular modality for treating BPD, I am seeing that treating it from a trauma standpoint in addition to a behavioral one, has been the most effective.


If you find yourself feeling hopeless and feeling lost and thinking you will never be able to live a fulfilling life or have healthy relationships, just know that this isn’t your destiny. You may feel stuck, but with time, good therapy, and patience, you can break these patterns and have a life worth living.


It won’t happen overnight and it will be hard and often frustrating, but it can happen. Don’t be afraid to try therapy. While trauma changes the brain, so does healing. Give yourself this gift. You deserve to have a life worth living.







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