Improving the Nation’s Health

Step One: Reduce Toxic Stress in Early Childhood

Healthy development and survival depend not only on the capacity of our stress response systems to ramp up rapidly in the face of a threat, but also on their ability to return to baseline when the threat has been mastered. Thus, stress can be positive when associated with moderate, short-lived physiological responses, and tolerable when supportive relationships facilitate adaptive coping. However, when children do not receive protective support and nurturance from adults, significant stress can be associated with toxic physiological complications.

“When we refer to toxic stress, we mean that literally,” says Shonkoff. “We’re talking about the stress-activated release of a stream of hormones in the body whose persistent elevation can disrupt the wiring of the brain and the functioning of the immune system.”

Each of us has a threshold of stress that we reach before our body responds. This “set point” is highly individualized and determined by both genetics and by early childhood experiences. Normal activation of the body’s stress management systems produces a variety of physiological reactions. These include an increase in heart rate, rise in blood pressure, and elevation of stress hormone levels (such as cortisol, a corticosteroid ­hormone produced by the adrenal gland). Such responses prepare the body to deal with a threat—to fight or to flee.

Children who have supportive relationships with adults are more likely to master the usual array of childhood stresses and bring their physiological responses back to baseline quickly. But for children who experience abuse, neglect, family or neighborhood violence, or other serious traumas in the absence of protective relationships, the threat is continuous. Their physiological stress responses remain activated at high levels, which lead to persistently elevated cortisol that can undermine the architecture of the developing brain. Cortisol also increases blood pressure and blood sugar levels and suppresses the immune system.

These children develop a lower set point for activation of their body’s stress management systems which they will carry into adulthood. For them, the impacts of toxic stress become a way of life.

How Early Experience Affects Adult Health

Children who experience toxic stress in early childhood may develop a lifetime of greater susceptibility to stress-related physical illness, such as cardiovascular disease, hypertension, and diabetes, as well as mental health problems, including depression, anxiety disorders, alcoholism, and other types of substance abuse. Early toxic stress can also lead to deficiencies in learning, memory and self-regulation—all issues related directly or indirectly to health.

In broad terms, unbuffered stress exacts a high price from children and undermines the health of the nation. Council Member W. Thomas Boyce, Sunny Hill Health Centre / BC Leadership Chair in Child Development and Professor of Pediatrics at the University of British Columbia, has found that children who experience bullying, violence in school, or other threats to safety may react biologically to stress in ways that make them particularly vulnerable to colds, sore throats, and ear infections. At the same time, children gain resistance to such illnesses when they live in nurturing, low-stress environments.

The 1995-97 Adverse Child Experiences (ACE) study, conducted by the Kaiser Permanente Department of Preventive Medicine in San Diego, examined the childhoods and health histories of nearly 20,000 Americans. Two-thirds reported at least one “adverse” childhood experience (including neglect, abuse, and other family dysfunctions); 20 percent reported three or more qualifying experiences. The higher the number of adverse childhood experiences, the more likely the adult participant was to have multiple health risk behaviors and poor outcomes—including cancer, stroke and diabetes. Negative coping behavior was found to produce higher rates of alcoholism, obesity, depression, liver disease, heart disease, suicide, sexually transmitted diseases, and unintended pregnancies.

“People who have been abused may use behaviors such as cigarette smoking, heavy alcohol use, overeating, promiscuity and drug use as a way of coping with damaging experiences much earlier in life,” according to Dr. Vincent Felitti, a principal ACE investigator.

Hostility is one of those coping mechanisms. Science now shows that children who are mistrusting and hostile (an expected response to abuse or neglect) are more likely to develop physical symptoms that indicate greater vulnerability to later diseases. In 2002, the results of long-term research at the University of Pittsburgh showed that early hostility levels are linked to later high blood pressure and body weight, unhealthy blood fats, and insulin resistance. These factors are tied to greater risk for type II diabetes and heart disease.

Abuse also distorts the biological maturation process, according to a 1991 study by Dr. Frank Putnam, a psychiatrist at the National Institute of Mental Health in Rockville, MD. He reported that the sexual maturation of children who have been sexually abused occurs at an accelerated rate, with increases in levels of the stress-related hormone cortisol as well as in testosterone and other hormones. These children advance a year or two ahead of their peers who have not been abused, resulting in an undesirable acceleration of sexual maturity. This condition may contribute to their greater vulnerability as adult victims of abuse, thereby perpetuating the cycle of abuse with younger individuals, or both.

For information about commonly used terms in Council publications, see Definitions.