The Impact of Childhood Trauma on Brain Development and Function

Abstract

current article will provide an overview of the research literature on how trauma impacts brain development. An exploration of trauma is outlined, as well as the sources of childhood trauma. Understanding how the brain develops and how trauma impacts this development provides the means to better understand traumatized children. This article is a literature review focusing on the brain and the impact of traumatic experiences on both brain development and function.

The Effects of Childhood Trauma on the Developing Brain

Many researchers suggest that early childhood trauma can be described as those that happen before the age of six (Murray & Fortinberry, 2006). These experiences lie at the root of most long-term psychological illnesses, such as depression, anxiety, major depressive disorder, bipolar disorder, and personality disorders (Anda et al., 2005). In addition, this trauma can alter the chemistry and physiology of the developmental brain (Beers & DeBellis, 2002). Among mental health professionals, there seems to be a lack of agreement on what exactly constitutes childhood trauma (Christopher, 2004).

Inflicting serious emotional trauma on children is a common occurrence in society (Lubit et al., 2003). Unfortunately, it has only been in the last 30 years that there has been research on the consequences of adverse childhood experiences (ACEs) (Teicher et al., 2003). Prior research explored traumatic experiences in adulthood only. This could be because young children were believed to be unaffected by trauma because they will not remember the experience later in life (Maas et al., 2018). However, current research supports childhood trauma having significant impacts on the emotional, cognitive, social, and physical functioning of the child (Lubit et al., 2003). This literature review will briefly discuss brain development and then further discuss how trauma can negatively impact it. To understand the impact trauma has on the brain, it is necessary to define trauma and explain the sources of childhood trauma.

Childhood Trauma

Definitions

In psychiatry, “trauma” has been defined as an experience that is emotionally painful, distressful, or shocking. These experiences often result in long-lasting physical and mental effects (Heide & Solomon, 2006). An academic report (Myers, 1992) from the American Academy of Pediatrics defined childhood abuse as the damaging interaction between the child and the caregiver that becomes typical of the relationship. According to (Felitti et al., 1998), child neglect is the negligent treatment of a child by a caregiver that indicates harm or threatened harm to the child’s health or well-being. In addition to physical, sexual, and verbal abuse and neglect, making a child feel worthless, unloved, or insecure can also be a form of damaging act (Myers, 1992).

Trauma can further be defined as a serious injury or shock to the body from physical or emotional violence that causes lasting damage to the psychological development of the person (Maas et al., 2018). This psychological damage can cause illness in the form of neurosis, which is excessive and irrational anxiety and worry (Maas et al., 2018). A specific form of trauma is attachment trauma (Anda et al., 2005), which can be defined as the physical or sexual abuse, rejection, cruelty, or lack of response from caregivers that, in turn, fails to provide the basic needs of a child. This type of trauma influences the child’s ability to appropriately attach to his/her caregiver, which can also lead to failure to thrive. Infants are completely defenseless and rely on the caregiving of an adult to survive. The response of a caregiver determines the attachment style the child will incur, which is crucial for the survival of the infant (Myers, 1992).

Sources of Childhood Trauma

There are multiple factors that may influence the child’s reaction to the trauma; according to Maas, Laceulle, and Bekker (2018), the trauma’s specific nature influences the child’s reaction. Some examples of factors that influence the child’s reaction include the duration of the event, trauma involving loved ones as the victim, the involvement of physical injuries, and the child’s perception of the traumatic outcome. Another source of trauma can occur during pregnancy. Developing fetuses may experience trauma through the use of malnutrition and substance abuse. These experiences can create significant deficits in brain development; prenatal vulnerabilities minimize healthy development and create biological and behavioral complications in the child’s brain (Bremner, 2005).

Childhood trauma differs from ordinary stress in childhood in multiple ways. According to (Christopher, 2004), trauma occurs suddenly and catches a child off guard. In addition, these events are unpredictable and atypical for a child. Lastly, the child can feel a great sense of helplessness and inability to cope. These factors all combined to create a terror response from the child. Sources of childhood trauma can come from accidental injury, illnesses, catastrophes, physical and sexual abuse, interpersonal and community violence, observation, traumatic loss, and psychological trauma and neglect (Christopher, 2004; Perry, 2006). In addition, certain traumatic experiences, such as sexual abuse, have a high chance of retraumatization (Maas et al., 2018).

The Brain

Overview of Brain Development

All necessary brain structures are present at birth; however, brain development continues long afterward at a significant pace. After birth, the brain becomes dependent on environmental cues to establish how neurons will differentiate and create their final neural network (Perry, 2002). According to Heide & Solomon (2006), the brain is not done developing until a person is in their mid-twenties. During the first year of life, the brain will grow to and a half times its birth size (Anderson et al., 2000). The size of the brain at age four is 90 percent the size of the adult brain (Perry, 2006).

The brain develops in a sequential hierarchical manner, and different areas of the brain are fully functional at different periods in childhood (Perry, 2006). Due to differences in maturing brain functioning, there are critical periods in which childhood should experience certain things for normal brain development (Perry, 2006). Because brain development occurs mostly in early childhood, this critical period has the most enduring effect on how the brain functions in the future (Perry, 2006).

Impact of Trauma on the Brain

According to Perry (2006), neural connections in the brain are mostly formed by the age of four, when a child’s brain becomes ‘hard-wired’ from repetitive experiences. Neurons that originate from the brain stem (lower in the brain) send signals to neurons in the higher portions of the brain (Perry, 2006). If these neurons are not firing properly due to trauma, the entire brain’s functioning is impaired. The longer the child is left in a neglectful environment, the more difficult it will be to stimulate correct brain development.

The brain allows one to be connected to other humans in the present moment; it is the brain’s job to protect us in situations we cannot flee from. Research from Perry (2006) depicts a hierarchy of brain function. It is suggested that the human brain is organized from the most parsimonious regions (brain stem) to the most complex regions (frontal lobe). The functions that happen in the brain stem are most simple and reflexive (body temperature regulation) (Bremner, 2005). Brain structure can be altered by the incoming messages from one’s senses (Bremner, 2005). The formation of memory is created by pattern, intensity, and frequency of neural activity (Anderson et al., 2000). The more frequently a certain pattern of neurons fires together, the more permanent the memory. Experience can, therefore, create a processing template in which new information is inputted (Anderson et al., 2000).

According to (Teicher et al., 2002), traumatic stress can have an effect on bodily functioning. There has been research that suggests children exposed to repeated trauma have differing levels of cortisol, a critical stress-sensitive hormone (Lubit et al., 2003). Cortisol is a necessary hormone for healthy functioning; however, it can be damaging if levels are too high or low. Stress can impact cortisol levels significantly, even in children as young as six months (Lubit et al., 2003).

When a child’s brain is exposed to chronic trauma, the developing brain and the child may actually begin to feel the hyper-aroused state experienced during trauma is normal (Bremner, 2005). What is unhealthy, unsafe, and damaging to the child is what feels most familiar to him/her. Trauma can cause abnormal development of the hippocampi (cognition and memory) and the amygdala (emotions are located here) (Teicher et al., 2002).

Trauma can also weaken the connection between the two hemispheres and, in turn, can be the cause of an underdeveloped cerebral cortex. Neural functioning can also be inhibited by trauma (Perry, 2002; Perry, 2006). Other researchers (Beers & Debellis, 2002) found similar results relating to trauma and brain development. Trauma-induced cortisol levels can adversely affect brain development by accelerating loss of neurons, abnormal pruning, delayed myelination, and stunted neurogenesis (Anda et al., 2005).

One common reaction to danger has been labeled the ‘fight or flight’ reaction. As an individual begins to feel threatened, the brain orchestrates a complex total-body response in which the brain and body shift along an arousal continuum (Perry, 2006). All aspects of functioning are altered during a traumatic event: feeling, thinking, and behaving (Anderson et al., 2000). In an alarm state, the individual has no time for abstract thinking and planning; they are using the most primitive part of their brains to react and survive (Perry, 2002). This increases the sympathetic nervous system activity and causes an increased heart rate, blood pressure, and respiration. These physiological increases can also cause hypervigilance, in which the child tunes out all non-critical information (Anderson et al., 2000).

The adverse childhood experiences (ACE) study is an ongoing collaboration that analyzes the relationship between multiple categories of childhood trauma (ACEs) and the health and behavioral outcomes later in life (Karatekin, 2016). Results from this study indicate a strong correlation between exposure to trauma in the first eighteen years of life and multiple negative adult behaviors. These include smoking, obesity, physical inactivity, depression, suicide attempts, alcoholism and substance abuse, sexually transmitted diseases, and cancer (Felitti et al., 1998).

Conclusion

As this literature review demonstrated, the experience of childhood trauma has a substantial influence on a child’s brain development. The brain acts as the operating center, receiving all new information and having to make sense of it. This means that a child who experiences trauma will filter all his/her new experiences through this lens of traumatic events. This may cause a minor stressor to be a large trigger for the child, initiating the stress response. The stress response may cause the child to perceive past trauma, making the child feel threatened and hypervigilant. In order for professionals to work with children who suffer from childhood trauma, it is important for them to think about the trauma and how it impacted the client’s brain before intervening with treatment.

References

Murray, J., & Fortinberry, T. (2006). Early childhood trauma. Journal of Trauma Nursing, 13(2), 69-73.
Anda, R. F., et al. (2005). The enduring effects of abuse and related adverse experiences in childhood. European Archives of Psychiatry and Clinical Neuroscience, 256(3), 174-186.
Beers, S. R., & DeBellis, M. D. (2002). Neuropsychological function in children with maltreatment-related posttraumatic stress disorder. The American Journal of Psychiatry, 159(3), 483-486.
Christopher, C. (2004). Defining child abuse in psychiatry: Pathologizing the victim. Child and Adolescent Social Work Journal, 21(5), 421-442.
Heide, K. M., & Solomon, E. P. (2006). Mental health professionals’ perceptions of childhood trauma. Journal of Interpersonal Violence, 21(12), 1613-1631.
Lubit, R., Rovine, M. J., Defrancisci, S. J., & Eth, S. (2003). Child and adolescent psychiatrists’ views on early childhood trauma. Child Psychiatry & Human Development, 33(1), 19-34.