Toxic stress, a hormone-stimulated response to a difficult situation, contributes to the achievement gap between lower-social-class and middle-class children. Research in medicine, economics, and psychology shows that across school-work, behavior, and health, children exposed to more frightening or threatening experiences are at greater risk of the damaging effects of toxic stress. African-American children and children from lower-income families are more likely to be exposed to frightening or threatening experiences.

Studies that I reviewed for a recent report published by the Economic Policy Institute (EPI), “Toxic Stress and Children’s Outcomes,” show that children who are more exposed to frightening and threatening experiences have worse outcomes than children less exposed but similar in age, gender, race, maternal education level, parent relationship status, and family income.

If educators hope to close the achievement gap that exists in our country, we need to understand more about how these experiences are affecting the children in our classrooms every day.

What is toxic stress?  

We’ve all heard of the “fight or flight” response. It is an essential survival mechanism. In a normal response to a threat, the amygdala, hypothalamus, and adrenal and pituitary glands produce adrenaline, cortisol, and other hormones. When released, these hormones can affect almost every tissue and organ in the body. They send the brain a signal to attack the threat or escape from it.

Stress hormones increase the body’s heart rate, blood pressure, and breathing. They dilate the blood vessels and the bronchioles in the lungs, so that more oxygen reaches the brain, muscles, and vital organs. They facilitate pupil dilation to improve vision.

When threats are rare or infrequent, the resulting stress is tolerable and can sharpen a person’s senses, such as the adrenaline rush that makes us focus and heightens our senses.

But when events are severely threatening or happen frequently, the stress can become toxic. In these cases, hormones that are protective in a normal stress response can be over- or under-produced, changing how the brain and body react. This hormone disruption can stunt brain growth and diminish activity in the prefrontal cortex, which controls decision-making, attention, memory, learning, and emotional regulation. It can weaken the immune system and disrupt the metabolic system. The stress response no longer heightens faculties, but diminishes them, and performance deteriorates.

Severe, repeated, or prolonged events that can provoke a toxic stress response include abuse; having a parent or relative incarcerated; witnessing violence; neglect; financial hardship; homelessness; racial discrimination; parental separation; placement in foster care; property loss or damage from fire or burglary; or having a family member become seriously ill or injured, hospitalized, or die.

Protective factors

We know that exposure to such events does not necessarily result in toxic stress. Appropriate emotional support and protective factors can help children respond constructively to these events. However, when such conditions are absent, diminished, or negative, they can weaken protective factors and increase the chances that even normal stress escalates to a toxic level.

When children have a network of stable, responsive relationships and caregivers with the financial, psychological, and social resources to nurture and protect them, they are more likely to cope successfully with threatening events. Such resources help the return to normal of a child’s stress hormones.

Living in a neighborhood residents experience as orderly can be protective. Equally, living in a disorderly neighborhood can exacerbate children’s toxic stress risk and impede parents’ ability to protect children from it. Noise, litter, graffiti, conflict with neighbors, not having safe public spaces to congregate, when isolated or occasional, are unlikely to be frightening or dangerous. Yet, when compounded, they can exacerbate a feeling of disorder and lack of control over one’s environment and decrease parents’ sense of well-being and ability to respond positively to their children’s needs.

Living in a neighborhood with a high concentration of incarcerated parents diminishes the protective capacity of affected families and erodes the overall protective capacity of the neighborhood. It is more concentrated in segregated, low-income, African-American neighborhoods and contributes to the disruption of normal family support systems.

Finally, a school’s climate protects against toxic stress. Children are better able to develop the skill of self-regulation in schools and classrooms that are emotionally supportive and responsive to all students. This occurs in classrooms where teacher and student relationships are positive, with teachers maximizing students’ feelings of autonomy, competence, and social connectedness.

Racial and social class differences

African-American children and children from low-income families are more likely to be exposed to prolonged, frequent, or major frightening or threatening events.

According to the research we reviewed, children from families with incomes below $20,000 are 18 percent more likely than children from higher-income families to have been exposed to a frightening or threatening event in their lifetime. Also, they are more likely to have been exposed to additional threatening experiences.

Black children are 45 percent more likely than white children to have been exposed to one frightening or threatening experience. Again, they are more likely to have been exposed to additional experiences.

Different outcomes 

In the EPI report, we looked at research comparing the academic, behavioral, and health outcomes of children exposed to frightening and threatening events with outcomes of children not exposed.

Academic: The share of children in their last month of kindergarten who could not independently read a simple book was much greater for those who had been exposed to three or more frightening or threatening life experiences than for otherwise similar children who had not. The share of children with below average reading and math skills was greater for those who had been exposed to frightening or threatening experiences than for otherwise similar children. Far more did not understand basic conventions of print or a story that was read to them and were unable to name the letters of the alphabet.

Behavior: The share of children in their last month of kindergarten who had social problems (like acting younger than their age, or having difficulty getting along with peers), attention problems, or were aggressive and broke rules in school was much greater for children who had been exposed to frightening or threatening experiences than for those who were not.

Health: The share of children who suffered from ear infections and acute respiratory infections, eczema, viral infections, and obesity was greater for children who had been exposed to frightening or threatening experiences than for otherwise similar children. The share of teenage girls who became pregnant was much greater for those who had had frightening or threatening experiences than for those who had not.

Plausible pathways  

There are several factors that could plausibly explain why African-American children and children from low-income families are disproportionately exposed to frightening or threatening events.

Discriminatory criminal justice practices affect not only adults, but also bystanding children. African-American children are more likely to be exposed to police violence, racial profiling by law enforcement officers, and unwarranted attention by police to their caregivers. Such exposure increases the likelihood of children suffering from toxic stress.

Discrimination also occurs in schools: Black students are suspended more often, for longer periods of time, and receive greater punishment than their otherwise similar white peers. Discipline of black children is more frequently complemented with metal detectors, random searches, and/or student referral to law enforcement, none of which supports a safe and protective learning environment. Schools with a higher proportion of African-American students are more likely to criminalize student misbehavior.

Housing segregation, the result of a history of racially explicit federal, state, and local policies and practices, dilutes factors that can protect children living in low-income African-American neighborhoods from developing a toxic stress response. In such neighborhoods, high-quality health care is difficult to access. Public transportation is less reliable and accessible, increasing the risk of social isolation. Men in segregated African-American neighborhoods experience higher rates of incarceration, which damages the physical and mental health of the incarcerated, their children, families, and neighbors. All these factors are associated with a greater risk of exposure to frightening or threatening events and parenting that is less protective.


The most effective way to reduce the likelihood of toxic stress in children from low-income and racially segregated neighborhoods is to remove the social conditions that are likely to provoke or exacerbate a toxic stress response. Certain social, health, and education policies can strengthen factors that protect children against toxic stress and its causes.

First, parents, caregivers, and other adults can help protect children from developing a toxic stress response by being responsive, nurturing, and supportive. Home visiting programs or therapy services delivered by health workers or nurses can build adults’ capacity to provide safe, stable, and supportive relationships, which helps children develop positive coping skills.

Next, health care professionals can better diagnose and treat causes and symptoms of toxic stress, while strengthening protective factors that prevent experiences from provoking a toxic stress response in a child. All children should be screened routinely for such experiences. Health care professionals should be trained to understand how frightening or threatening events impact children’s cognitive, behavioral, and physical health outcomes, and screen and treat children for any resulting complications.

Finally, some school-based approaches can mitigate the effects of toxic stress and its causes. All adults working in school settings should receive training to understand how frightening or threatening experiences affect children’s schoolwork, behavior, and health. Adults can learn to respond appropriately and support children’s self-regulation skills and social and emotional learning. For example, when a child is behaving in a confrontational way, or has withdrawn, adults can de-escalate unproductive behavior by emotionally connecting with the child and removing the child from the overwhelming context before redirecting the child toward schoolwork. Such protective approaches should be integrated into the curriculum, into daily academic and nonacademic activities, and into how adults relate to children.

To mitigate racially discriminatory practices in schools that can contribute to toxic stress in children, educators should understand the characteristics, prevalence, and effects of racially biased school disciplinary practices. Teachers and administrators should collect and publicly report on school disciplinary data, including demographic information about who is removed from classrooms and from schools, and for how long and on what basis. Reflecting on these data and aggregating them at the district and state levels can help educators challenge bias in schools.

Offset toxic stress

There is no way that we know to exactly measure the relative effect of toxic stress on children’s cognitive, behavioral, and health outcomes. But researchers and informed practitioners, whose work is the basis of this article, judge that it is an important cause of disadvantaged children’s depressed outcomes.

Furthermore, this work reports population averages: Not all children exposed to frightening and threatening experiences will suffer adverse effects. Some will do better than most, while others will do worse. But, on average, it is less likely for children who are exposed to such experiences to do as well as children not exposed to such experiences.

As health care professionals have started to turn their attention to this important problem, so too should educators and education policymakers. Short of changing the conditions in which low-income children live, high-quality support for parents and parents-to-be should be accessible. Programs to offset the effects of toxic stress should be deployed in schools of concentrated disadvantage, including programs to effectively support educators. Policymakers and educators should improve public awareness of this insidious morbidity.

Leila Morsy ( is a research associate at the Economic Policy Institute and a senior lecturer at Flinders University, in Adelaide, Australia. This article is adapted from “Toxic Stress and Children’s Outcomes,” by Morsy and Richard Rothstein, which was published by the Economic Policy Institute in May 2019.

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