The Traumatized Child's Brain Development
Traumatized Children: How Childhood Trauma Influences Brain Development by Bruce D. Perry, M.D., Ph.D.
But soon I had to ask her about what had happened. She knew that was why I was there; I knew she knew that was why I was there. All of the adults in her ‘new’ life had sooner or later returned her to that night.
"What happened to your neck?" I asked, pointing to the two scars running from behind her ear to the front of her throat. She acted as if she did not hear me. She did not change her expression. She did not change the pace of her coloring.
I repeated the question. She took her crayon and scribbled over her well-formed, disciplined picture but gave no verbal response.
Again I asked.
Sandy stood up, grabbed a stuffed animal, held it by a tuft of hair and slashed at the neck of the animal with the crayon. As she slashed she repeated "It’s for your own good, dude." Over and over - a stuck recording.
She threw the animal to the floor, ran to the radiator, climbed up and jumped off - again and again. She did not respond to my verbal warnings about being careful. Finally, I rose and caught her on one of her jumps. She melted into my arms. We just sat together for more minutes. I felt her frenzied breathing slow and then almost stop. And then, in a slow, robotic monotone, she told me about that night.
An acquaintance of her mother came to their apartment. "Mama was yelling, the bad guy was hurting her; I should have killed him." "I came out of my room and mama was asleep - then he cut me - he said "It’s for your own good, dude."
The assailant cut her throat - twice. Sandy immediately collapsed. Later she regained consciousness and attempted to ‘wake up’ her mother. She took milk from the refrigerator and gagged when she tried to drink some. She gave some to her mother -- ‘she was not thirsty’.
A three-year-old, throat-cut child, weeping, whimpering, comforting and seeking comfort from her naked mother’s hog-tied, bloody, cold body. The mother’s multiple stab wounds oozed at first - then there was nothing but drying, ‘sticky’ blood. Sandy wandered that apartment for eleven hours before anyone came.
Sandy was alone - her world forever changed. Her entire being was altered - the way she thinks, the way she behaves, the way she feels, the way she grows. Her brain is etched with the memories of terror. She carries elements of this trauma with her everyday. She carries elements of her terror into every relationship and every classroom. In so many ways, she was robbed of her future, robbed of her true potential.
Sadly, Sandy is not alone. In the United States alone from 1996 to 1998 there were more than 5 million children exposed to some form of severe traumatic event such as physical abuse, domestic and community violence, motor vehicle accidents, chronic painful medical procedures and natural disasters. These experiences can have a devastating impact on children. Beginning with Lenore Terr’s landmark work, investigators over the last twenty years have determined that more than thirty percent of children exposed to these kinds of traumatic events will develop serious and chronic neuropsychiatric problems. The most common are Post-traumatic Stress Disorders (PTSD). PTSD has been studied primarily in adult combat veterans. Indeed, the United States has spent billions of dollars on research and clinical services for the 1 million veterans from the Vietnam era suffering from PTSD. In contrast, the twenty million (or more) children with PTSD are among the least understood, under-studied and inconsistently served groups in the United States.
Trauma and the Developing Brain
To help Sandy and millions of other traumatized children, we need to understand how the brain responds to threat, how it stores traumatic memories and how it is altered by the traumatic experience. Yes, altered. All experience changes the brain – good experiences like piano lessons and bad experiences like living through a tornado as it destroys your home. This is so because the brain is designed to change in response to patterned, repetitive stimulation. And the stimulation associated with fear and trauma changes the brain.
Over the last twenty years, neuroscientists studying the brain have learned how fear and trauma influence the mature brain, and more recently, the developing brain. It is increasingly clear that experience in childhood has relatively more impact on the developing child than experiences later in life. This is due to the simple principles of neurodevelopment.
The functional capabilities of the mature brain develop throughout life, but the vast majority of critical structural and functional organization takes place in childhood. Indeed, by the age of three the brain has reached 90 % of adult size, while the body is still only about 18 % of adult size. By shaping the developing brain, experiences of childhood define the adult. Neurodevelopment is characterized by (1) sequential development and ‘sensitivity’ (the brain "grows" from brainstem to the cortex) and (2) ‘use-dependent’ organization ("use it or lose it"). The mature organization and functional capabilities of brain reflect aspects of the quantity, quality and pattern of the somato-sensory experiences of the first years of life. The sequential and use-dependent properties of brain development result in an amazing adaptive malleability, ensuring that, within its specific genetic potential, an individual’s brain develops capabilities suited for the ‘type’ of environment he or she is raised in. Simply stated, children reflect the world in which they are raised. If that world is characterized by threat, chaos, unpredictability, fear and trauma, the brain will reflect that by altering the development of the neural systems involved in the stress and fear response.
The Neurobiological Responses to Threat
When a child is threatened, various neurophysiological and neuroendocrine responses are initiated. If they persist, there will be ‘use-dependent’ alterations in the key neural systems involved in the stress response. These include the hypothalamic-pituitary-adrenal (HPA) axis. In animal models, chronic activation of the HPA system in response to stress has negative consequences. Chronic activation may "wear out" parts of the body including the hippocampus, a key area involved in memory, cognition and arousal. This may be occurring in traumatized children as well. Dr. Martin Teicher and colleagues have demonstrated hippocampal/limbic abnormalities in a sample of abused children.
Another set of neural systems that become sensitized by repetitive stressful experiences are the catecholamine systems including the dopaminergic and noradrenergic systems. These key neurochemical systems become altered following traumatic stress. The result is a cascade of associated changes in attention, impulse control, sleep, fine motor control and other functions mediated by the catecholamines. As these catecholamines and their target regions (e.g., amygdaloid nuclei) also mediate a variety of other emotional, cognitive and motor functions, sensitization of these systems by repetitive re-experiencing of the trauma leads to dysregulation in many functions. A traumatized child may, therefore, exhibit motor hyperactivity, anxiety, behavioral impulsivity, sleep problems, tachycardia and hypertension. In preliminary studies by our group, we have seen altered cardiovascular regulation (e.g., increased resting heartrate) suggesting altered autonomic regulation at the level of the brainstem. In other studies, clonidine, an alpha2 adrenergic receptor partial agonist has been demonstrated to be an effective pharmacotherapeutic agent, presumably by altering the sensitivity of the noradrenergic systems. Studies by Dr. Michael DeBellis and colleagues have demonstrated other catecholamine and neuroendocrine alterations in a sample of sexually abused girls. These indirect studies all support the hypotheses of a use-dependent alteration in the brainstem catecholamine systems following childhood trauma.
Implications of Trauma-related Alterations in Brain Development
All experiences change the brain – yet not all experiences have equal ‘impact’ on the brain. Because the brain is organizing at such an explosive rate in the first years of life, experiences during this period have more potential to influence the brain – in positive and negative ways. Traumatic experiences and therapeutic experiences impact the same brain and are limited by the same principles of neurophysiology. Traumatic events impact the multiple areas of the brain that respond to the threat. Use-dependent changes in these areas create altered neural systems that influence future functioning. In order to heal (i.e., alter or modify trauma), therapeutic interventions must activate those portions of the brain that have been altered by the trauma. Understanding the persistence of fear-related emotional, behavioral, cognitive and physiological patterns can lead to focused therapeutic experiences that modify those parts of the brain impacted by trauma.
Our evolving understanding of neurodevelopment suggests directions for assessment, intervention and policy. Primary among these is a clear rationale for early identification and aggressive, pro-active interventions that will improve our ability to help traumatized and neglected children. The earlier we intervene, the more likely we will be to preserve and express a child’s potential.