by Alan M. Solomon, Ph.D.

Intense and/or ongoing stress for children can severely impact healthy development.  Literally, stress can impact how the brain is constructed, in ways that impair a child’s abilities to respond to stress effectively, to learn successfully, and to behave in more adaptive ways.  Longer-term health is also at risk.  These are the findings of a working paper from the Center on the Developing Child at Harvard (“Excessive Stress Disrupts the Architecture of the Developing Brain”; www.DEVELOPINGCHILD.HARVARD.EDU). Intuitive observations about stress are increasingly being supported by empirical data.

During healthy development for children, coping with mild or even moderate stress prompts an increase in heart rate and blood pressure, as well as the release of stress hormones, like adrenaline and cortisol.  Some stresses are unavoidable, even when children are well-nurtured and cared for, due to pressures and challenges that are an inherent part of life. Some waiting to be fed is one obvious example for infants.  If there are supportive relationships with adults, the effects of such stresses are eased, and the child returns to a healthy baseline.  In these experiences during early childhood, a healthy stress response system develops within the child that will help the child cope with future stresses more effectively.

If the stress is extreme, long-lasting, and without adult support, it becomes “toxic stress”.  Such toxic stress damages and weakens the body’s stress response system, impairs brain development, and has lifelong repercussions for health.  The key variables in evaluating toxicity are:  duration, intensity, timing, the degree to which stresses are controllable, frequency, and the availability of supportive adults.

The Harvard study group identified three levels of stress:

  • Positive:  moderate, short-lived, a normal part of life.  A child learns to adjust to this unavoidable and even essential part of healthy development.


  • Tolerable: has a possibility for damage, but it is over a limited time period.  The brain can recover and reverse any harmful effects, if there is a context of adult support.  Examples of this stress include death or serious illness of a loved one, an accident, acrimonious parental separation, or persistent discrimination.  Without adult support, such stresses can become toxic.


  • Toxic: powerful, frequent, prolonged activation of stress management systems in the child. If this is chronic, uncontrollable, and in early developmental periods, without adult support, it becomes damaging in ongoing and fundamental ways.  Some parts of the brain produce more neurons (basic nerve cells) and become over-active, and over-reactive.  The parts of the brain impacted in this way have to do with fear, anxiety, and impulsive responses. Other parts of the brain involved in reasoning, planning and behavioral control produce fewer neurons, and are thus less engaged and helpful.  The basic stress response system is changed, so that a child responds to lower thresholds of stimuli; in other words, situations that are not powerfully stressful to other children, prompt a more intense, frequent, and longer stress response in these children exposed to toxic stress early in life.

Current science informs us that our stress response system and its interrelated brain circuits actually work to help us respond adaptively to challenges in our environment.  When there is a threat of some kind, signals to the brain prompt changes in brain chemistry and the release of hormones in the body to help us respond effectively to that concern.  During pregnancy and early childhood, our brains are especially malleable (“plastic”, per neurologists) and can be deeply affected by stress.

Toxic stress impacts the brain circuits and hormone systems, such that our stress response system becomes poorly controlled.  We become overly reactive to stresses, and/or we are slow to shut down the stress response system once the pressures have eased.  This becomes a life-long pattern of responses.  Children may respond with a feeling of being threatened and will likely respond impulsively where there is little or no real threat.  For example, they may perceive anger in a facial expression when that expression is really more neutral or mild.  They will remain anxious and aroused long after a perceived threat has eased.

A well-functioning brain system for stress responses is crucial for healthy development.  Life by its very nature presents novel or potentially threatening situations as part of daily experiences.  Being able to cope effectively with such stresses is part of healthy development, even survival at times.  If a poorly controlled stress response system is activated too often or for too long, a child’s health and well-being is damaged.  The child – and then later, the adolescent and adult – becomes more vulnerable to behavioral and/or physiological disorders over their lifetime:  depression, anxiety, alcohol/drug abuse, heart disease, diabetes, and stroke, to name a few prominent risks that are epidemic.

The mechanics of stress responses involve elevated levels of adrenaline and cortisol, as well as activity levels in the hypothalamus and pituitary glands.  Adrenaline mobilizes energy and alters blood flow to help the body respond to threat.  Cortisol also mobilizes energy, enhances certain types of memory, and activates the immune system in the short-term; longer-term, it suppresses the immune system and types of memory functioning and can lead to metabolic syndrome, loss of bone minerals, and atrophy of muscle tissue.  Prolonged stresses of a more intense nature thus can not only impact where neurons are developed in the brain (“brain architecture”), but also impair the ability to regulate stress responses, develop and make use of memory, learn, and have effective immune system responses to illnesses.

In addition to direct stresses affecting children (think of child abuse of course, but also living in a war zone or an economically deprived community, for example), less direct stress also has a significant impact.  Pregnant mothers who are undergoing high levels of stress, or mothers whose stress affects their ability to be attuned to their baby, also affect the stress response system in the baby, as well as the child’s brain development.  Animal studies of pregnant rats under greater stress reveal that their babies are more fearful and reactive to stress, compared to offspring whose pregnant mothers are not exposed to higher levels of stress.  Mother rats that provide inattentive care have offspring with similar issues, as well as a poorer production of growth factors that encourage brain development and repair.

Once beyond infancy, these baby rats have been evaluated to have impaired memory and learning, as well as more age-related memory and cognitive issues.  It is encouraging that in these animal studies, when “rich environments” with “opportunities for exploration and social play” are provided, the animals do compensate to some degree for the prenatal stress and postnatal neglect.  This compensation is literally in the basic structures and chemistry of the brain.

The implication of these animal studies is clear:  a child’s relationship with the mother and caregivers (including the prenatal period) is critical in how a child develops his stress responses early in life.  If there is a “secure relationship” the child will have a more controlled stress hormone reaction when dealing with stress.  This child will be more able to explore the world, meet challenges, and experience some fear without the adverse neurological impact of chronically elevated adrenaline or cortisol. If the relationship is “insecure or more disorganized”, the child will experience higher stress hormones even when only mildly frightened.  Phrased from the other direction, a “sensitive and responsive caregiver” with a toddler will likely encourage their child to have lower stress responses, even if the youngster is a more “temperamentally anxious or fearful child.”

With more mothers working outside the home in recent decades, quality early care and educational programs outside the home become important in this context of elevated stress responses.  Elevated responses to stress are the result of poor quality child care, a higher child to adult ratio, and more harsh interactions with caregiving adults. If a child is temperamentally more shy, supportive child care is even more crucial to avoid increased stress hormones;  these children are more prone to developing more symptomatic behavior than more outgoing children, if child care is less supportive.

Economic hardship impacts child development as well.  Chronic poverty, adverse conditions, overcrowding, noise, poor housing, separations from parents, violence, and family turmoil are all powerful variables in the child’s developing brain architecture and stress response systems.  If the mother is depressed, this is all worsened further.  Abuse or neglect prompts elevated cortisol levels, which continue even after a child might be moved to a safer and more loving home.  This is especially true for children who experience overt trauma.  As an adolescent, these kids often have high blood pressure.  As adults, inflammation factors in blood workups are in place, as are higher risks for heart disease.

What are the policy implications of this growing body of evidence?

  • Interventions can change the outcome.  Consistent, predictable, nurturing care during pregnancy, infancy and early childhood can lead to more positive adaptation and better outcomes for children, simply because their brain development and stress response systems are improved.
  • Parents who are struggling to raise their children (and during pregnancy as well) need stronger, informed, and formal support services to bolster their parenting efforts. Many adults lack basic knowledge about child development, as well as skills needed to help at-risk or symptomatic children struggling with stress response difficulties.  This knowledge and skill set in parents can be taught and nurtured.
  • High quality early childcare and educational programs, especially with stable, supportive relationships with caring adults, will greatly benefit children at risk of tolerable or toxic stress.
  • Many professionals and first-responders lack training to identify children at risk and/or mothers who are depressed or overwhelmed. Such training will improve access to assessment and then services.
  • Children who are possible victims of abuse or neglect need assessment of their developmental status. Their functioning in intellectual, language, emotional, social and early educational spheres needs to be evaluated, with services provided as indicated.
  • As a matter of routine, all adults living in poverty who are in contact with social services of some sort, should also have their children screened for possible developmental issues. Such children may well have experienced stress without the adult care needed to ameliorate its impacts.

Some programs are already in place. Parent Child Interaction Therapy is one such program, first developed at the University of California at Davis.  Home visits and mentoring by child development specialists for young mothers are also available in some communities.  Well-attuned psychotherapy and educational support services for parents are often available with professionals in private practice as well.  Our future generation’s well-being depends on this help.

Alan M. Solomon, Ph.D. is a clinical psychologist in Torrance, CA. A member of the Independent Psychotherapy Network, he can be reached at (310) 539-2772, or

Copyright 2017 by Alan M. Solomon, Ph.D.