Effects of Stress on Brain Development

In situations of prolonged stress, brain development and physical growth may slow down or even stop. Prolonged exposure to the cortisol released during the stress response can cause permanent damage to a developing brain and negatively affect the immune system.

Experiences that are most often repeated in a child's environment are those that create connections within the child's brain. When a child regularly experiences chaos or stress, her brain becomes wired to respond to threatening, stressful experiences. Even after a threat has subsided, her brain may continue to respond as if the stress is still present, and she may overreact in some situations. A child whose brain is wired to respond to stress may have difficulty learning. Brain development may even slow down. Later in life, a child who has experienced excessive or chronic stress is likely to have difficulty coping with life's demands.

The first area of the brain to develop is the brain stem. It is responsible for the most basic functions necessary for survival. It is the first part of the brain to react when a threat is perceived. It sends signals of the threat to other parts of the brain. In a fully developed brain, the frontal lobe then takes action. It controls reasoning and judgment and is responsible for making rational responses in a threatening situation. An infant or young child whose frontal lobe is not fully developed does not have the capacity to respond rationally when under stress.

A child's response to stress will be controlled by the more primitive areas of the brain. In order to become calm, an infant or young child needs her caregivers to comfort and reassure her that she is safe. If her environment is constantly threatening and she does not have a nurturing, consistent caregiver to make her feel safe, the primitive areas of the brain will be used more, and areas responsible for emotional control and rational decision-making may not develop fully. Warning signs of imbalance in brain development may include anxiety, impulsiveness, hyperactivity, poor impulse control, lack of empathy and poor problem-solving skills.