Impacts of Stress and Trauma
on the Growing Brain

Some Messages of Neurobiology of the Brain

• The most rapid rate of growth of the human brain happens in utero;

• The human brain grows to 90% of its potential adult size within the first 3 years of life – making and reinforcing neurological connections, “more than 1 million new neural connections are formed every second (Harvard Centre of the Developing Child, June 2021)”

• The final 10%  of growth happens in the next 25 years from age 3 to approximately 28;

• A child is born with their brain stem fully developed which means they are primed towards safety and survival;

• The language centres of the brain are being developed in the 3rd trimester of pregnancy at which time the neonate can hear and begins to learn the language of their primary carers;

• Genes and experience shape the developing brain;

• Our brains are wired to seek relationship: “The right-brain develops before the left brain which doesn’t begin it’s growth spurt until the second year (Schore, A. 2015)”; this means emotional attachment (right-brain) has primacy over cognitive development (left brain).

• Neuro-plasticity of the brain is at it’s best in early childhood which means this is when it is most vulnerable and also has the greatest potential for healing.

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Some Key Messages of Stress and Trauma

• Because of negative physiological effects of stress hormones on the developing child, exposure to trauma can impact the neuro-sequential development of each domain of the brain leading to physical and cognitive impairment;

• A child’s experience of trauma can be as early as when they are in utero with the mother’s experience of verbal and physical abuse, and other stress inducing situations, having a direct effect on the developing foetus;

• Because a child is wired to seek connection, when the primary care giver is not safe (physically OR emotionally) this results in the child not feeling safe;

• Feeling unsafe is more than exposure to physical danger; it is also the absence of emotional and psychological safety;

• Episodes of hyper AND hypo arousal are just as damaging on the brain architecture as each other;

• Trauma can be passed down the generations or within a family, community or culture;

• Exposure to trauma in utero and prior to the second year of development leads to sub-cortical responses to triggers (Fight, Flight, Freeze, Feign Death).

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Possible* impacts of developmental trauma on children and young people

• Developmental trauma can affect the size of the brain through limited stimulation reducing the number of neural connections leading to low density and size in comparison to same age peers.

• Exposure to loud environments – verbal abuse, slamming doors, breaking and smashing objects - can lead to audio sensory issues impacting on receptive language and inability to filter out background noises leading to overwhelm responses.

• Expressive language can be affected by limited “serve and return”, positive communication, experiences with a safe care giver.

• Children and young people being in a constant state of hypervigilance, scanning the environment for perceived danger means they are not able to engage their higher order thinking, leading to minimal engagement in learning.

• The Executive function of the brain that is responsible for impulse control, attention and focus may be affected due to interruptions to the neuro-sequential order of development often leading to diagnoses of ADHD and ODD.

• Affect regulation is impacted in the first year of life where there have been limited soothing and regulatory experiences with a consistent and safe care giver. This can impact the child or young person’s awareness of emotions and their ability to learn how to self-sooth.

• Infants and young children who experience limited or no loving and safe touch, regardless of access to food and water, can lead to a failure to thrive and in more extreme cases, death.
  * Note: these are generalised impacts of developmental trauma. The impact on the individual will depend on a number of influences including the developmental stage when the trauma was first experienced, the severity and duration.

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