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The Neurobiology of Trauma




One of the most disturbing aspects of trauma is that it can be experienced as though the traumatic event is continually happening. This occurs because traumatic experiences can disrupt the storage or encoding of memories. Because of this, traumatized individuals can often struggle to develop narratives that serve to process their traumatic experiences. Typically, the brain's memory network integrates information in a manner that combines contextualization in time and space along with sensory, affective, and behavioral memory with our conscious awareness. However, during states of trauma this process gets disrupted leaving memories encoded in a manner associated more strongly with somatic (bodily), sensory, emotional, and non-verbal memories. Because of this imbalance in encoding it is through this process of talking through and developing narratives for traumatic events that neural network integration can begin to take place resulting in psychological healing and the resolution of disruptive symptoms.


What Is Trauma?

When we speak of trauma, we often think of post-traumatic stress disorder (PTSD) as the classic example of the effect trauma can have on an individual. PTSD can be broken down into three main clusters of symptoms, which consist of hyperarousal, intrusion, and avoidance. Hyperarousal is commonly seen in exaggerated startle reflexes, agitation, anxiety, and irritability. Intrusions involve a lack of a sense of distance from the traumatic event in time or place and can manifest as flashbacks or nightmares. Finally, avoidance can take many forms ranging from denial and repression to dissociation in more severe cases.


What Is Complex Trauma?

Another frequent but less commonly discussed form of trauma is that of complex PTSD. In complex PTSD early, prolonged, and inescapable trauma occurring throughout childhood results in adverse effects on physiology, development, and overall functioning of the individual. Due to its pervasiveness this manifests as enduring personality traits and coping strategies that while conceivably adaptive at the time of the traumatic events, can leave an individual vulnerable to future traumas as well as predisposed to developing compulsive disorders, somatization disorders (in which emotions are converted into physical symptoms), and borderline personality disorder.




But Why Does This Happen?

The basic building blocks of a traumatized brain underlie both the neurochemistry of post-traumatic stress disorder as well as complex PTSD. Trauma can cause disturbances in the integration of cognitive, sensory, and emotional processing and the more severe or prolonged the trauma the more negative and far-reaching its effects. There are number of predictable patterns of biochemical changes that occur as the result of states of acute stress.


Why Does Trauma Present in so Many Different Ways?

A number of neurotransmitters play a role in the development and maintenance of trauma symptoms. Norepinephrine is the neurotransmitter responsible for preparing us for fight or flight responses and is also involved in encoding traumatic memories. Associated symptoms can include arousal, anxiety, irritability, and an exaggerated startle response. High levels of dopamine are also associated with traumatic events and correlate with hypervigilance. This can show up as paranoia and perceptual distortions when under stress. Reduced levels of serotonin are correlated with higher levels of irritability, arousal, depression, violence and even suicide. Elevated endogenous opioids serve as our natural analgesics to relieve pain but can have a profoundly negative impact on cognition, memory, and reality testing. Higher levels are associated with the emotional blunting, and dissociation, commonly seen in traumatized individuals. Finally, glucocorticoids have been shown to contribute to decreased hippocampal volume and related memory deficits as well as negative effects on the immune system, which can contribute to trauma survivors’ experiences of being fragile or vulnerable long after the traumatic event has subsided.



How is Trauma Treated?

There are a number of different approaches to formulating and treating trauma. When broken down to their core ingredients the “working through” of traumatic events essentially requires talking through prior traumas with supportive others in a safe environment. This essentially creates the neurobiological conditions for the reestablishment of neural coherence. It is my hope that by providing this broad conceptualization of trauma so as to include any number of events that can disrupt the delicate balance and integration of the various systems of the brain, that more individuals may be recognized as experiencing the effects of trauma. Finally, I want to reassure both therapists and patients alike that many types of therapy have proven successful in reintegrating neural processing and reducing or eliminating the cascade of symptoms caused by traumatic events.


If you or someone you know is experiencing the effects of trauma, I encourage you to consider reaching out to a therapist as you are not alone and real and lasting changes are possible.


-Shea McTaggart, Psy.D.

Director of Psychological Assessment