The changes in brain structure and chemical activity caused by childhood trauma can have a wide variety of effects on children’s behavioural, social, and emotional functioning.
Persistent fear response
Chronic stress or repeated trauma can result in a number of biological reactions, including a persistent fear state (National Scientific Council on the Developing Child, 2010). Chronic activation of the neuronal pathways involved in the fear response can create permanent memories that shape the child’s perception of and response to the 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.
Children with a persistent fear response may lose their ability to differentiate between danger and safety, and they may identify a threat in a non-threatening situation (National Scientific Council on the Developing Child, 2010). For example, a child who has been maltreated may associate the fear caused by a specific person or place with similar people or places that pose no threat. This generalised fear response may be the foundation of future anxiety disorders, such as PTSD (National Scientific Council on the Developing Child, 2010).
When children are exposed to chronic, traumatic stress, their brains sensitise the pathways for the fear response and create memories that automatically trigger that response without conscious thought. This is called hyperarousal. These children may be highly sensitive to nonverbal cues, such as eye contact or a touch on the arm, and they may be more likely to misinterpret them (National Scientific Council on the Developing Child, 2010). Consumed with a need to monitor nonverbal cues for threats, their brains are less able to interpret and respond to verbal cues, even when they are in an environment typically considered non-threatening, like a classroom. While these children are often labelled as learning disabled, the reality is that their brains have developed so that they are constantly on alert and are unable to achieve the relative calm necessary for learning (Child Trauma Academy, n.d.).
Increased Internalising Symptoms
Childhood trauma can lead to structural and chemical changes in the areas of the brain involved in emotion and stress regulation (National Scientific Council on the Developing Child, 2010). For example, childhood trauma can affect connectivity between the amygdala and hippocampus, which can then initiate the development of anxiety and depression by late adolescence (Herringa et al., 2013). Additionally, early emotional abuse or severe deprivation may permanently alter the brain’s ability to use serotonin, a neurotransmitter that helps produce feelings of wellbeing and emotional stability (Healy, 2004).
Diminished Executive Functioning
Executive functioning generally includes three components: working memory (being able to keep and use information over a short period of time), inhibitory control (filtering thoughts and impulses), and cognitive or mental flexibility (adjusting to changed demands, priorities, or perspectives) (National Scientific Council on the Developing Child, 2011). The structural and neurochemical damage caused by maltreatment can create deficits in all areas of executive functioning, even at an early age (Hostinar, Stellern, Schaefer, Carlson, & Gunnar, 2012; National Scientific Council on the Developing Child, 2011). Executive functioning skills help people achieve academic and career success, bolster social interactions, and assist in everyday activities. The brain alterations caused by a toxic stress response can result in lower academic achievement, intellectual impairment, decreased IQ, and weakened ability to maintain attention (Wilson, 2011).
Delayed Developmental Milestones
Although neglect often is thought of as a failure to meet a child’s physical needs for food, shelter, and safety, neglect also can be a failure to meet a child’s cognitive, emotional, or social needs. For children to master developmental tasks in these areas, they need opportunities and encouragement from their caregivers. If this stimulation is lacking during children’s early years, the weak neuronal pathways that developed in expectation of these experiences may wither and die, and the children may not achieve the usual developmental milestones. For example, babies need to experience face-to-face baby talk and hear countless repetitions of sounds in order to build the brain circuitry that will enable them to start making sounds and eventually say words. If babies’ sounds are ignored repeatedly when they begin to babble at around six months, their language may be delayed. In fact, neglected children often do not show the rapid growth that normally occurs in language development at 18–24 months (Scannapieco, 2008). These types of delays may extend to all types of normal development for neglected children, including their cognitive-behavioural, socio-emotional, and physical development (Scannapieco, 2008).
Weakened Response to Positive Feedback
Children who have experienced trauma may be less responsive to positive stimuli than non-maltreated children. A study of young adults who had been maltreated found that they rated monetary rewards less positively than their peers and demonstrated a weaker response to reward cues in the basal ganglia areas of the brain responsible for reward processing (Dillon et al., 2009).
Complicated Social Interactions
Toxic stress can alter brain development in ways that make interaction with others more difficult. Children or youth with toxic stress may find it more challenging to navigate social situations and adapt to changing social contexts (Hanson et al., 2010). They may perceive threats in safe situations more frequently and react accordingly, and they may have more difficulty interacting with others (National Scientific Council on the Developing Child, 2010b). For example, a maltreated child may misinterpret a peer’s neutral facial expression as anger, which may cause the maltreated child to become aggressive or overly defensive toward the peer.
Watch this video from Beacon House – a child trauma service from the United Kingdom – on how trauma affects the brain. Please note that the clip contains themes and images that may be distressing to some. Please feel free to stop watching the video if you are distressed.
Child Trauma Academy. (n.d.). The amazing human brain and human development. Retrieved from http://www.childtraumaacademy.com/amazing_brain/index.html
Dillon, D. G., Holmes, A. J., Birk, J. L., Brooks, N., Lyons-Ruth, K., & Pizzagalli, D. A. (2009). Childhood adversity is associated with left basal ganglia dysfunction during reward anticipation in adulthood. Biological Psychiatry, 66, 206–213.
Hanson, J. L., Chung, M. K., Avants, B. B., Shirtcliff, E. A., Gee, J. C., Davidson, R. J., & Pollak, S. D. (2010). Early stress is associated with alterations in the orbitofrontal cortex: A tensor-based morphometry investigation of brain structure and behavioral risk. Journal of Neuroscience, 30, 7466–7472.
Healy, J. M. (2004). Your child’s growing mind: Brain development and learning from birth to adolescence. New York: Broadway Books.
Herringa, R. J., Birn, R. M., Ruttle, P. L., Burghy, C. A., Stodola, D. E., Davidson, R. J., & Essex, M. J. (2013). Childhood maltreatment is associated with altered fear circuitry and increased internalizing symptoms by late adolescence. Proceedings of the National Academy of
Sciences of the United States of America, 110, 19119–19124.
Hostinar, C. E., Stellern, S. A., Schaefer, C., Carlson, S. M., & Gunnar, M. R. (2012). Associations between early life adversity and executive function in children adopted internationally from orphanages. Proceedings of the National Academy of Sciences of the United States of America, 109, 17208–17212.
National Scientific Council on the Developing Child. (2010). Persistent fear and anxiety can affect young children’s learning and development (Working Paper 9). Retrieved from http://developingchild.harvard.edu/index.php/resources/reports_and_working_papers/working
National Scientific Council on the Developing Child. (2011). Building the brain’s “air traffic control” system: How early experiences shape the development of executive function (Working Paper 11). Retrieved from http://developingchild.harvard.edu/index.php/resources/reports_and_working_papers/working
Scannapieco, M. (2008). Developmental outcomes of child neglect. The APSAC Advisor, Winter. Elmhurst, IL: American Professional Society on the Abuse of Children.
Wilson, K. R., Hansen, D. J., & Li, M. (2011). The traumatic stress response in child maltreatment and resultant neuropsychological effects. Aggression and Violent Behavior, 16(2), 87–97.