A seminal 1998 study conducted by the Centers for Disease Control and Prevention and Kaiser Permanente revealed that adults who had a higher number of adverse childhood experiences-including various types of abuse, neglect, and family challenges, such as domestic abuse, alcoholism, and the incarceration of a household member-had poorer health and behavioral outcomes. The researchers found that the more a child is exposed to adverse experiences, the greater the risk in adulthood of conditions such as alcoholism, chronic obstructive pulmonary disease, depression, ischemic heart disease, cancer, and liver disease. Such children are also at heightened risk for domestic violence, financial stress, sexually transmitted infections, and suicide.
The results of this study have since been echoed and further explored by numerous researchers and health organizations. In 2014, the Center for Youth Wellness in San Francisco published a report noting that nearly two-thirds of California adults had been exposed to at least one adverse childhood experience. Such experiences have the potential to lead to what's known as toxic stress.
The Center on the Developing Child at Harvard University categorizes children's stress response to adverse experiences into three tiers: positive, tolerable, and toxic. A positive stress response-in which a child might experience a brief or mild change in heart rate or stress hormone levels, for example-can be triggered by situations considered to be a normal part of a child's life, such as meeting new people, overcoming frustration, or receiving a vaccination. With adequate support from adults, children can not only manage these stressors but also learn from them and grow. A tolerable stress response may be triggered by an event such as the death of a family member, a serious illness or injury, a contentious divorce, a natural disaster, or an act of terrorism. Although challenging, these stressors tend to occur for a limited amount of time and can be overcome with adult support. A toxic stress response, on the other hand, is the result of strong, frequent, or prolonged activation of the body's stress response in the absence of a supportive adult relationship. It can disrupt brain circuitry during a sensitive developmental period in a child's life, eventually leading to permanent changes in brain structure and function, causing chronic physical and mental illnesses.
HOW PREVALENT ARE ADVERSE CHILDHOOD EXPERIENCES?
Published in 2013, the results of the 2011 National Survey of Children's Exposure to Violence revealed that about 41% of children and youths had experienced a physical assault in the previous year. One in 10 had experienced an assault-related injury. About 2% of all children surveyed had experienced sexual assault in the last year, but almost 11% of 14-to-17-year-old girls had been sexually assaulted. More than one in 10 children experienced caregiver maltreatment; of these children, almost 4% experienced physical abuse.
Not surprisingly, race and geography play an important role in adverse childhood experiences. In a 2018 brief based on the findings of the 2016 National Survey of Children's Health, researchers noted that one in 10 children in the United States had experienced three or more adverse childhood experiences; as many as one in seven children living in Arizona, Arkansas, Montana, New Mexico, and Ohio had experienced three or more such experiences. Nationally, 61% of black children and 51% of Hispanic children were found to have experienced at least one adverse childhood experience, compared with 40% of white children and 23% of Asian children.
In 2012, the American Academy of Pediatrics (AAP) published a policy statement on early childhood adversity and toxic stress, emphasizing the importance of the "inextricable interactions" among family and social relationships, environmental influences, and genetic predispositions. The organization recommended that health care professionals
* gain a better understanding of the social, behavioral, and economic causes of lifelong disparities in health.
* routinely screen patients for toxic stress.
* educate parents, child care providers, teachers, policymakers, and the public on the implications of toxic stress.
* advocate for investments in community activities, such as after-school programs, and in early childhood mental health services.
"While there is a growing recognition[horizontal ellipsis] regarding the need to assess children and adults for ACEs [adverse childhood experiences], perceived barriers persist," says Antonia M. Villarruel, PhD, RN, FAAN, professor and Margaret Bond Simon Dean at the University of Pennsylvania School of Nursing. "These include lack of standardized tools to assess ACEs, increased assessment and resulting patient and family visits, lack of awareness or availability of support for patients and their families, and an unawareness of the relation of ACEs to physical, social, and emotional aspects of health."
Complicating matters is the multigenerational effect of toxic stress. According to the AAP, a parent who has had adverse childhood experiences may have a lower threshold for stressful events and poorer coping skills than a parent without such experiences. For this reason, identifying parental adverse childhood experiences-and promoting resilience-may be crucial when assessing a child's risk of toxic stress.
IMMIGRATION POLICIES AND TOXIC STRESS
In addition to race, geography, and a family history of adverse childhood experiences, immigration status is a risk factor for toxic stress. According to a 2017 report from the Kaiser Family Foundation, the fear and anxiety of immigrant families has escalated under the Trump administration, which has introduced more restrictive immigration policies. This fear is being felt by 12 million U.S.-born children who have undocumented parents and by families who are in the country lawfully but fear a reversal of their status. Exacerbating these children's anxieties are such stressors as more prevalent bullying at school (the people interviewed in this report said they perceived Muslims and Latinos to be the primary targets of such bullying), increased financial strain caused by a scarcity of job opportunities for undocumented parents, and the ceasing of such family routines as picnics and barbecues in public parks out of fear of deportation.
"Separation from parents, temporary shelters, disruption, limited access to forming relations with caring adults or caregivers, lack of regular schooling, and less than optimal food are some of the conditions immigrant children are confronting," says Villarruel. "These experiences, like other ACEs, have been shown to affect neurodevelopment; negatively impact social, emotional, and cognitive development; and can result in the adoption of health risk behaviors. These health effects can last for generations and affect us all as a society. The dehumanization of these children puts us at risk as a country that has long championed and welcomed refugees and other immigrants."
Tackling toxic stress requires an integrative approach that involves children, their families, clinicians, communities, and state and federal policymakers. According to a 2014 review in the journal Children, beneficial measures include referring a child at risk for toxic stress to a social worker, psychologist, or psychiatrist; attenuating the stress response through breathing techniques, guided imagery, music therapy, biofeedback, and mindfulness; and providing caretakers with parenting classes, home visits, telephone support, family-based programs, social resources, problem-solving and information-seeking skills, and peer support. If these approaches are not always possible in a busy practice, clinicians can still provide written information about breathing techniques, for instance, along with a list of free smartphone apps on biofeedback and websites for stress reduction. Although there is no standardized tool for screening children for toxic stress, the AAP lists several useful resources on its website (go to http://www.aap.org/en-us/advocacy-and-policy/aap-health-initiatives/resilience/P). -Dalia Sofer