Effects of Child Maltreatment on Early Brain Development

by Child Welfare Information Gateway

"Harry Chugani observes '... We can have individuals who, based on early experiences, are in effect "hard-wired" for negative behaviors.' Some neuroscientists consider this an overstatement; others find it too mild"

- Shore, 1997

Babies' brains grow and develop as they interact with their environment and learn how to function within that environment. When babies' cries bring food or comfort, they are strengthening the neuronal pathways that help them learn how to get their needs met, both physically and emotionally. But babies who do not get responses to their cries, and babies whose cries are met with abuse, learn different lessons. The neuronal pathways that are developed and strengthened under negative conditions prepare children to cope in that negative environment, and their ability to respond to nurturing and kindness may be impaired.

Stress

Brief periods of moderate, predictable stress are not problematic; in fact, they prepare the child to cope with the general world. The body's survival actually depends upon the ability to mount a response to stress. But prolonged, severe, or unpredictable stress-including abuse and neglect-during a child's early years is problematic. The brain's development can literally be altered by these experiences, resulting in negative impacts on the child's physical, cognitive, emotional, and social growth.

Chronic stress sensitizes neural pathways and over-develops certain regions of the brain involved in anxiety and fear responses, and often results in the under-development of other neural pathways and other regions of the brain. Children who experience the stress of physical or sexual abuse will focus their brains' resources on survival and responding to threats in their environment. Children who experience the chronic stress of neglect-e.g., remaining hungry, cold, scared, or in pain-will also focus their brains' resources on survival. This chronic stimulation of the brain's fear response means that the regions of the brain involved in this response are frequently activated. When they are, other regions of the brain, such as those involved in complex thought, can not also be activated and are therefore not "available" to the child for learning.

Because the brain ultimately controls all bodily functions, experiences that alter brain development also alter our bodies' responses. Studies have shown that "... the overwhelming stress of maltreatment experiences in childhood is associated with alterations of biological stress systems and with adverse influences on brain development". One example of the effects of early maltreatment on brain and body functions involves the chemical cortisol. Cortisol is a hormone that helps the body prepare to cope with stress through its effects on metabolism and the immune system. Studies have shown that many infants and children who have been maltreated have abnormal secretions of cortisol, indicating that their bodies' responses to stress have been impaired. More research is needed to understand why this occurs and what effects this may have on the children's emotional and social development, but this information provides some evidence of altered brain activity in maltreated children.

A key issue in understanding altered brain development in children who have been maltreated is that the way in which their brains develop is often a very adaptive response to their negative environment, but it is maladaptive in other environments. If a child lives in a threatening, chaotic world, his brain will be hyper-alert for danger; his survival may depend on it. But if this environment persists, and the child's brain is focused on developing and strengthening its strategies for survival, other strategies may not develop as fully. If a child lives in a world that ignores him, if he is not provided with appropriate stimulation for growth, his brain will focus on survival from day to day and may not fully develop healthy cognitive and social skills. The result may be a child who has great difficulty functioning when presented with a world of kindness, nurturing, and stimulation. It is an unfamiliar world to him; his brain has not developed the pathways and the memories to adapt to this new world.

Persistent Fear Response

Fear is necessary to our basic survival. We must be able to detect threats and respond. Indeed, the brain is uniquely designed to sense, process, and store threatening information and to mobilize the body in response to threats. All parts of the brain and body are used in this response. "This total neurobiological participation in the threat response is important in understanding how a traumatic experience can impact and alter functioning in such a pervasive fashion".

Chronic stress or repeated traumas can result in a number of biological reactions. Neurochemical systems are affected which can cause a cascade of changes in attention, impulse control, sleep, and fine motor control. Chronic activation of certain parts of the brain involved in the fear response (such as the hypothalamic-pituitary-adrenal [HPA] axis) can "wear out" other parts of the brain such as the hippocampus, which is involved in cognition and memory. Early experiences of trauma can also interfere with the development of the subcortical and limbic systems which can result in extreme anxiety, depression, and difficulty forming attachments to other people. And chronic activation of the neural pathways involved in the fear response can create permanent "memories" which shape the child's perception of and response to his environment. While this adaptation may be necessary for survival in a hostile world, it can become a way of life that is difficult to change, even if the environment improves.

Dissociative and Hyper-arousal Responses

Dr. Bruce Perry, former head of the Child Trauma Academy at Baylor College of Medicine in Houston, Texas, offers this example of dissociative and hyper-arousal responses in the same child for different events.

"T is a twelve year old girl. From birth until age five she lived in a household characterized by domestic violence. During this time, she was noted to be quiet, compliant, "tuned out," daydreamed and generally "a good little girl." She reports little memory of the fighting but her mother describes finding her in her bed, rocking, with covers over her head after some of the fights in the home. At age 12, her mother re-married but unfortunately, episodes of domestic violence resumed in this household. This time, however, T was loud, combative, angry and would run away from the home each time these events took place. She was noted to have "attention" problems at school that turned out to be hypervigilance. Rather than "tuning out" and withdrawing into a dissociative shell, this child was sensitized to fighting and had dramatic and pronounced hyperarousal during conflict."

- Perry

Hyper-arousal

When a child is exposed to chronic, traumatic stress, his brain sensitizes the pathways for the fear response and literally creates memories such that his fear response becomes almost automatic; he doesn't really think about it. This is called a state of "hyper-arousal." His brain has adapted to a world that is unpredictable and dangerous; it is hyper-vigilant, focused on non-verbal cues that may be threatening. The regions of the brain involved in the hyper-arousal response are always "on," and because of this, the child may frequently experience hyperactivity, anxiety, impulsivity, and sleep problems. Hyper-arousal is most common in older children and in males.

In the state of hyper-arousal, similar to Post Traumatic Stress Disorder (PTSD), the brain's alarm system becomes particularly sensitive to "threatening" environmental cues, and the child may respond anxiously or aggressively. The regions of the brain involved in the hyper-arousal response become re-activated when the child is exposed to a reminder of the earlier trauma (such as thinking or dreaming about it), to perceived threats (which may not seem threatening to others), and sometimes to generalized reminders (signals). Perry presents an example of an 8-year-old boy who became extremely agitated-sobbing and hysterical-when the staff at his group home refused to cut up his hot dog before he ate it. The child had been sexually abused by his father and other men. Foods such as hot dogs, bananas, and popsicles evoked his brain's fear response, and until the "signal" was removed or altered, his brain experienced it as a threat. Another example is that of a child who had committed an impulsive, violent act and explained it by saying "I could tell he was going to jump me-he looked me in the eyes". In his mind, his brain, the simple act of looking him in the eye was perceived as a threat that required a defensive response.

Not only may children in a state of hyper-arousal react anxiously or aggressively to perceived threats, they may actually provoke threatening behavior from others in order to have some control over it. Predictability of threat is important. Children who have been victims of unpredictable physical or sexual abuse learn (consciously or unconsciously) that if abuse is going to happen, it is better to control when it happens. They may engage in aggressive, provocative behavior to elicit a predictable response. For example, a girl who has suffered repeated sexual abuse from her father may attempt to seduce a male teacher. She may believe that men will invariably try to have sex with her, so she tries to control when and with whom.

About the Author

www.childwelfare.gov
Formerly the National Clearinghouse on Child Abuse and Neglect Information and the National Adoption Information Clearinghouse, Child Welfare Information Gateway provides access to information and resources to help protect children and strengthen families. A service of the Children's Bureau, Administration for Children and Families, U.S. Department of Health and Human Services.