Neurobiology of Trauma

When a major stressor occurs, the hippocampus (involved in memory processing) and the amygdala (involved in the processing of emotions) are flooded with stress hormones.

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Child maltreatment is currently considered a large public health problem. That is why, during the last decades, there has been a rapid process in trying to understand the effects of exposure to traumatic life experiences in the psychopathology of children. But how does the neurobiology of trauma develop?

During recent years, clinical research has focused on explaining the impact of specific traumatic incidents and exposure to neglect and chronic abuse. Thus, different studies have shown that isolated traumatic incidents tend to produce conditioned responses to memories of the trauma.

Meanwhile, chronic abuse or recurrent exposure to traumatic events, such as exposure to repeated medical or surgical procedures, seems to have generalized effects on neurobiological development. Apparently, several facts contribute to the extent of the psychological damage that trauma produces in neurobiology:

  • The age at which children are traumatized for the first time.
  • The frequency of traumatic experiences.
  • Also the degree to which caregivers contribute to the event being traumatic.

Thus, we know that traumatic experiences can change brain structures and compromise emotional, cognitive and bodily functions, which weakens patients. However, the neurobiology of trauma is still poorly understood among specialists and there are few educational resources available, despite their prevalence.

In 2013, the American Psychiatric Association reviewed the diagnostic criteria for post-traumatic stress disorder (PTSD) in the Manual of Diagnosis of Mental Disorders. Thus, the disorder was included in a new category in the manual: Disorders related to trauma and stressors.

Post-traumatic stress disorder

Traumatic events can compromise emotional, cognitive and bodily functions. Thus, this produces debilitating symptoms for patients and a diagnosis of PTSD. In this way, trauma can occur:

  • During a specific event. For example, as a witness to family violence.
  • During a prolonged period. For example, the case of child abuse.

When a major stressor occurs, the hippocampus (involved in memory processing) and the amygdala (involved in the processing of emotions) are flooded with stress hormones. The individual can not process the traumatic experience as a completed event (although the threat no longer exists as such) and the memory remains active in the brain.

That is why the symptoms of PTSD can appear for a long time after the trauma has occurred. In fact, in 25% of cases there is a late onset of these symptoms.

The neurobiology of trauma: Affected areas

The neurobiological alterations of normal development induced by trauma include areas involved in the regulation of homeostasis. These are:

  • Brainstem and locus coeruleus.
  • Memory systems (including the hippocampus, amygdala and frontal cortex).
  • The brain areas included in the executive functioning:
    • Orbitofrontal cortex.
    • Cingulate cortex.
    • Dorsolateral prefrontal cortex.
  • Neuroendocrine system Included:
    • The hypothalamic-pituitary-adrenal axis (HPA).
    • All conceivable neurotransmitter systems.

Brain stem and mesencephalon

The systems that deal with the threats are the sympathetic and parasympathetic nervous system, which originate in the brain stem. Thus, early exposure to extreme threats and inadequate care affect, significantly and in the long term, the body’s ability to modulate the sympathetic and parasympathetic nervous systems in response to stress (16).


Some studies report that children who suffer PTSD and have been mistreated then excrete significantly higher concentrations of dopamine and norepinephrine than the control subjects, who have not suffered abuse.

Cardiac variability rate

Children who have been traumatized have a lower variability in heart rate compared to healthy subjects.


In general (and in contrast to cortisol studies in adults with PTSD), traumatized children

significantly higher cortisol levels than the control groups, which had not previously suffered trauma.

Limbic system

Research shows that adults still affected by the traumatic footprint and suffering from PTSD showed greater activation of the right amygdala when they were reminded of their trauma. This activation was accompanied by a lower activation of the speech center.

The hippocampus

People who have suffered trauma and developed PTSD can present a decrease in hippocampal volume in their neurobiology. Thus, Davidson and his collaborators have proposed that the impact of hippocampal involvement in psychopathology may be more evident in the processing of emotional information. Thus, children with damage to the hippocampus would be prone to show emotional behavior in inappropriate contexts.

Other areas affected in the trauma are:

  • Prefrontal cortex.
  • Hemispheric lateralization.
  • The cerebellum, corpus callosum and the integration of experiences.

Long-term effects of dysregulation of neurobiology in trauma

Loss of emotional self-regulation

The lack of capacity for emotional self-regulation is characteristic of children who have suffered chronic trauma. Their lack of self-regulation processes leads to problems with self-definition. Thus, these problems are reflected in:

  • The lack of a continuous and predictable sense of oneself, with a bad sense of separation and alterations of the body image;
  • Deficient modulated affect, as well as poor impulse control, including aggression against oneself and others, and
  • Uncertainty about the reliability and predictability of others, which can lead to distrust and problems related to privacy.
  • Learning and memory

Some characteristics of traumatized children are:

  • Tendency to hypervigilance. They worry about imminent danger and tend to attack ambiguous stimuli.
  • This affects the way they organize their perceptions of the world and is often associated with the development of widespread problems in learning and academic performance.
  • Limitation of your attention to sources of threat. Thus, they may show disinterest in response to things that other children may find challenging or stimulating.
  • Also the occurrence of paranoid ideas and erroneous perceptions.

Social problems

Children who have been exposed to violence tend to:

Having difficulty adapting their behavioral excitement to appropriate social demands.

As a result, they are often not in tune with others. In addition, they may give the impression of presenting intellectual disability in the years of primary school.

Physical illness

Other studies have shown that traumatized children are vulnerable to a variety of physical illnesses. As adults, they have between 10% and 15% more chance of getting cancer, heart disease and diabetes.

During adolescence they tend to engage in destructive acts against themselves and others. In addition, they are approximately 300% more likely than their peers who have not suffered trauma from participating in drug abuse, self-mutilation and violent and aggressive behavior against others.

Many children affected by trauma tend to communicate what has happened to them without words; positioning itself in front of the world as if it were a place full of dangers and activating neurobiological systems oriented to survival, even when objectively safe. Thus, while children can not talk about their traumatic experiences, it is likely that the trauma is expressed as an incarnation of what happened to them.

Therefore, the task of therapy in traumatized children is to help them develop a sense of physical mastery, in turn stimulating awareness of who they are and what has happened to them. In this way they will be able to understand what happens to them in the present and stop recreating the traumatic past in an emotional, behavioral and biological way