Strong, frequent, and/or prolonged adversity without adequate adult supervision or guidance.
— Harvard Center on the Developing Child

The Stress Response.

This survival mechanism existed throughout all of human evolution.

The human stress response, also known as the "Fight-or-Flight Response," is a neurobiological response that gives humans additional reactionary ability in life-threatening moments. In the pre-modern era, it drastically improved our survival rate when hunting or fleeing; in those times, our ability to survive rested solely on our body's reaction. A typical response works in the following fashion:

1. After the mind recognizes a stressful environment or a threat to life, it activates a collection of stress response systems that release different chemical compounds (i.e. hormones) into the bloodstream to prepare the body for a life-threatening situation. 

2. Once these compounds have entered the bloodstream, a number of survival-based, bodily reactions occur: increased heart rate, boosted energy, suppressed immune system, dulled pain, and much more.

3. After the stressor leaves the environment, the body no longer needs an activated stress response system. Thus, stress-signaling compound levels return to normal, and the associated reactions disappear.

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A Healthy Part of Life.

In our modern world, the "Fight-or-Flight Response" may seem out of place.

The stress we experience now typically pales in comparison to the threats of the ancient world, and we certainly encounter quite sparingly the same challenges that our primitive ancestors did. However, given that this is an evolutionary mechanism, it cannot simply be wished away. It can, though, be seen in a positive light.

When the stress response is triggered temporarily and mildly throughout a child's development, it plays an undeniably constructive role in their life. It fosters resilience, confidence, and certain coping mechanisms, all of which aid in their preparation for the adulthood. Conversely, though, when the stress response is more severe and less temporary, the story is entirely different. 

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If the stress response is extreme and long-lasting, and buffering relationships are unavailable to the child, the result can be damaged, weakened systems and brain architecture, with lifelong repercussions.
— Harvard Center on the Developing Child

Toxic Stress.

long-term stress response can disrupt a child's development—both in mind and in body.

For comparison, consider the feeling of illness that is associated with a fever. Its symptoms, such as sweating, headaches, and general weakness, are induced solely by the body's shift out of homeostasis. Likewise, during a human's stress response, the cascading of stress hormones shifts the body out of its natural state and into one of instability. The body, in the case of chronic stress and the lack of a supportive environment, can therefore face the same level of severity in bodily damage as having an illness without access to medicine.


The key component to defining toxic stress is in the lack of external support in the face of adversity.

The consequences of toxic stress can be curbed in the presence of support structures, such as parental guidance, friendship, etc. However, when no such relief exists, the effects are detrimental and potentially lifelong. The following elements are often found in environments of toxic stress:

  • Physical abuse
  • Emotional abuse
  • Chronic neglect
  • Exposure to violence
  • Caregiver substance abuse
  • Extreme economic hardship (Lack of consistency in one of the following necessities: food, water, or shelter)


Memory Impairment

Children who suffer from toxic stress have a higher risk of developing long- and short-term memory deficiencies.

Delayed Development

Chronic exposure to toxic stress during childhood can potentially stunt early development, especially in terms of brain physiology.

Behavioral Issues

Those experiencing toxic stress may adopt unstable moods, short attention spans, and lower impulse control.

Cardiovascular Issues

According to the CDC, children growing up in environments of toxic stress have a higher risk of developing cardiovascular disease during adulthood.

Mental Health Issues

Toxic stress can cause chemical imbalances and elevated stress hormone levels that may lead to numerous mental health issues.

Physical Harm

Aside from the internal injury, domestic elements of alcoholism, abuse, and other like dangers can pose a serious threat to physical well-being.


Read more about this topic in our resources page.

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1. "Slightly more than a third(37.5%) of the childhood victims of sexual abuse, 32.7% of those physically abused, and 30.6% of victims of childhood neglect met DSM-III-R criteria for lifetime PTSD."
From: Posttraumatic Stress Disorder in Abused and Neglected Children Grown Up, Cathy Widom 1999 (Cited 873 times)
2. Numbers in Neglect (United States): Emotional Neglect: 183/1000 Children Physical Neglect: 164/1000 Children
From: The neglect of child neglect: a meta-analytic review of the prevalence of neglect, Marije Stoltenborgh (2013) (Cited 142 times)

Banner Image courtesy of: Keith Negley