What Is Stress?

It is important to understand that not all stress is bad for brain development. In fact, some stress is helpful to child development. In the research literature there are three kinds of stress that are important to understand: positive, tolerable, and toxic stress.

Positive Stress

Positive stress is regarded as a normal, important and essential part of healthy development that occurs in the context of stable and supportive relationships. Characterized by brief increases in heart rate and mild elevations in hormone levels.

Example: A child with a supportive caregiver becomes frustrated, a child goes to school for the first time.

Tolerable Stress

Tolerable stress activates the bodies alert system to a greater degree and generally occurs within a time-limited period. If it is buffered by supportive caregivers/relationships that assist the child to adapt, this gives the brain an opportunity to recover from potentially damaging effects.

Example: Loss of a loved one, an accident, injury or repeated medical intervention.

Toxic Stress

Toxic stress can occur when a child experiences strong or frequent and/or prolonged stress without adequate support. Less-extreme exposure to toxic stress can change the stress system so that it responds at lower thresholds to events that might not be stressful to others, thereby increasing the risk of stress-related physical and mental health problems. In extreme situations, this prolonged type of stress can disrupt brain development and lead to lifelong problems in learning, behaviour, and both physical and mental health physiologic changes that may become permanent well into the adult years.

Example: Abuse or neglect, exposure to violence.

Source: http://developingchild.harvard.edu/science/key-concepts/toxic-stress/