Alberta Family Wellness Initiative (AFWI): Stress: how positive, tolerable, and toxic stress impact the developing brain

Photo Credit: Unsplash User  Andrew Branch

Photo Credit: Unsplash User Andrew Branch

In 2009, the Alberta Family Wellness Initiative (AFWI) engaged FrameWorks to validate the core story of brain development in the Alberta context.  Founded in 1999, the FrameWorks Institute is a U.S. organization that helps non-profits shape public discourse about specific topics in order to facilitate more informed decision-making.

For the core story of brain development, the process entailed communications experts working alongside neuroscientists and brain development scholars to develop a new way of communicating key concepts. Incorporating elements of linguistics, anthropology, sociology, and political science, this cross-boundary team worked to develop a new approach to sharing scientific information about early childhood and its connection to later health outcomes, including addiction.

Based on this work, the AFWI has created numerous communications assets to disseminate the core story among its stakeholders. Collectively, these materials are known as the Brain Story: a narrative that builds upon the core story of brain development to also incorporate science about adolescent and adult health outcomes.

Stress is one of the factors that shapes brain architecture in a developing child, but not all stress is the same. Whether it strengthens or weakens brain architecture has to do with the intensity of the stress, its duration, and whether supportive caregivers are present in the child’s life.

An article on the Alberta Family Wellness website discusses three types of stress response

  • Positive Stress:  Small challenges that create ‘positive stress’ (e.g. meeting new people; starting school, moving home) are healthy for development because they help prepare young brains and bodies for the larger challenges they will meet in the future.
  • Tolerable Stress:  More serious events, like a natural disaster or losing a loved one, aren’t good for us.  But if supportive caregivers are around to buffer the child’s stress response, these situations won’t do lasting damage to the brain.
  • Toxic Stress:  “Toxic stress”, which weakens brain architecture and can disrupt healthy development, occurs when no supportive caregivers are around to buffer a child’s response to repeated negative experiences. Young children whose brain development has been disrupted by toxic stress are at a much higher risk for later physical and mental health problems, including developing a mental illness such as depression, anxiety, or addiction.  The article points out that, because toxic stress can affect lifelong learning, social abilities, and health outcomes, it’s important to intervene early.

Research in Alberta shows that the most common triggers of toxic stress in children are:

  • Parental mental illness
  • Parental substance abuse
  • Parental abandonment or divorce
  • Emotional abuse
  • Sexual abuse
  • Physical abuse
  • Witnessing domestic violence
  • Emotional neglect
  • A family member in prison
  • Physical neglect

The article suggests important ways adults can intervene on behalf of children experiencing toxic stress:

  • Adults can help soothe children who are upset, calm their emotions, and help their stress response system come back to normal levels.
  • Adults can help teach children healthy coping skills to deal with stress later on.
  • Adults can provide help and support for caregivers (e.g. support to leave an abusive relationship, support to access quality addiction treatment) in order to target the source of stress for the child, so it doesn’t continue.
  • The article notes that evidence suggests the most effective interventions support caregivers and children both individually and through activities they work on together to strengthen their relationship.

A video explaining how negative experiences in childhood can impose large costs on brain health and development later in life can be found at TOXIC STRESS.

The article offers a brief explanation of the scientific understanding of how toxic stress operates in the body, concluding: “When stress hormones remain elevated over long periods of time, they produce wear and tear on the brain and certain biological systems, which are not designed to operate under constantly stressful conditions. In addition, cortisol in high concentrations is in itself damaging to biological tissues and can affect the stability of new brain circuits as they are forming. If cortisol levels remain high for long periods of time, the brain and body make adaptations to try to achieve balance in the system. This effect, which is called allostasis, can affect how our stress system regulates the stress response: the brain becomes less sensitive to the effects of cortisol such that it becomes harder to shut down our stress response system over time. “

Dr. Matthew Hill, from the University of Calgary, draws on neurobiology to discuss toxic stress, its effects on the brain, allostatic load, and later manifestation of disease in the following video link.  He takes a challenging and complex subject, and presents it in an entertaining and accessible presentation.  He talks about the role of the prefrontal cortex in regulating the limbic stress triggers.[Ref: July 10,2016 Keeping in Touch “If you can name it, you can tame it” 5-minute video by Dr. Dan Siegel demonstrating how ‘mindfulness’ practice can help regulate emotional reactivity.]

Dr. Hill explains how, in allostatic load, chronic exposure to stress results in repetitive excitation of neurons that creates change in the structure and function of the neurons.  In response to excessive excitation, neurons retract their dendrites, which represent their receptive field; this neuronal ‘shrinkage’ is an adaptive response to prevent cell death. This is an adaptive response, but the cost is that these neurons no longer perform optimally.  The two major brain regions where this has been documented are the hippocampus and the prefrontal cortex, leading to memory deficits and reduction of executive brain functioning (e.g. impairment of decision making, reduced impulse control, development of counter-productive habitual behaviours like smoking, eating disorders, drug use, etc.).  Impaired functioning of the prefrontal cortex and the hippocampus may also lead to a vicious circle of increased perception of stress and impaired termination of stress response.

Dr. Hill points out that, in the adult brain, this neuronal shrinkage is reversible following removal from the stressor as long as extreme stresses are not recurrent; the adult brain exhibits a high degree of plasticity and can bounce back from the effects of chronic stress. However, in the developing brain, from infancy through adolescence, there is not the same resilience after exposure to toxic stress.  Long-term studies investigating children raised in abusive or unstable family environments have found that they have an increased propensity for mental illness, inflammatory disease, and metabolic disorders.

In the presentation, Dr. Hill raises two findings of interest in addressing the effects of toxic stress on the developing brain:

  • Mild forms of stress in early life (such as briefly separating mother and child, or putting mother and child together into a new situation) may help to sculpt a stress resilient brain later in life.
  • Some research has demonstrated that interventions during adolescence, such as environmental enrichment, can ameliorate the effects of early life stress.


The authors make the case that we, as a community, can pay now or pay later, in dealing with the outcomes of toxic stress.  “Supportive environments for children are key, both to reduce their exposure to toxic stress and to create buffers of support to make stressful life events more bearable.  Trying to build new skills on a foundation of unstable brain circuits requires more work and is less effective than establishing strong brain architecture from birth….Better life outcomes could be achieved by decreasing the number and severity of adverse childhood experiences and by strengthening the relationships that protect young children from the harmful effects of toxic stress.”

The article concludes that, whilst it is important to have community supports in place to prevent toxic stress and build resiliency in children and caregivers. But because we can’t always prevent toxic stress before it begins, it is paramount to ensure that all children have the support of at least one caring adult in their lives to help them calm their emotions and cope with the stress. Evidence is clear that this adult support can turn experiences that would be toxic into experiences that are tolerable.

The National Scientific Council on the Developing Child has produced a working paper “Excessive Stress Disrupts the Architecture of the Developing Brain, which can be accessed at:  EXCESSIVE STRESS DISRUPTS THE ARCHITECTURE OF THE DEVELOPING BRAIN

The working paper starts from the position that the future of any society depends on its ability to foster the healthy development of the next generation. ”Extensive research on the biology of stress now shows that healthy development can be derailed by excessive or prolonged activation of stress response systems in the body and the brain, with damaging effects on learning, behavior, and health across the lifespan. Yet policies that affect young children generally do not address or even reflect awareness of the degree to which very early exposure to stressful experiences and environments can affect the architecture of the brain, the body’s stress response systems, and a host of health outcomes later in life.”

As well as direct exposure to toxic stress, “significant maternal stress during pregnancy and poor maternal care during infancy both affect the developing stress system in young animals and alter genes that are involved in brain development.”  However, “positive experiences after infancy in young mammals, such as being exposed to an environment rich in opportunities for exploration and social play, have been shown to compensate to some degree for the negative behavioral consequences of prenatal stress and postnatal neglect.”

The working paper also indicates that there appears to be genetic variability in individual responses to early stressful experiences, but there is evidence the “positive early caregiving can decrease the likelihood of these adverse outcomes, demonstrating that beneficial environmental influences can moderate the impact of genetic vulnerability…Research has shown that the presence of a sensitive and responsive caregiver can prevent elevations in cortisol among toddlers, even in children who tend to be temperamentally fearful or anxious,” and “the quality of the early care and education that many young children receive in programs outside their homes also plays an important role in whether (and to what extent) their brains are exposed to elevated stress hormones early in life.”

The authors of the working paper stress two significant points important in guiding policy decision-making:

  • Science does not support the claim that infants and young children are too young to be affected by significant stresses that negatively affect their family and caregiving environments.
  • Notwithstanding the preceding statement, there is no credible scientific evidence that supports the conclusions that all young children who have been exposed to significant early stresses will always develop stress-related disorders.

The working paper expresses concern that, despite a rich and growing scientific knowledge base illuminating the multiple adverse effects of early life stresses, including long-term impacts on children’s ability to learn, adapt and cope with stress throughout their lives, little attention has been paid to the development and implementation of strategies to prevent or reduce significant stressors that affect children and families.  Areas of particular concern raised include:

  • Limited availability of family leave after the birth or adoption of a baby, and little financial support for parents who wish to stay at home with their newborns, but do not have the economic resources to make ends meet in the absence of paid employment.
  • Limited availability of convenient, affordable, high-quality early care and education, flexible scheduling options for jobs and health care, and community-based support for working parents at all income levels who are struggling to balance the demands and responsibilities of work and raising children.
  • Limited efforts to reduce high job turnover in child care programs, which affects the quality of relationships between adults and the children under their care.
  • Limited availability of expert help and promising interventions for parents and providers of early care and education who are struggling to manage behavioral difficulties in young children, noting increases in the expulsion of children from preschool programs and “the growing ‘off-label’ use of prescription drugs, particularly stimulant and anti-depression medications, for increasingly younger children with emotional or behavioral difficulties.”
  • Limited access to clinical expertise in mental health for very young children and their families, especially early specialized treatment for “young children who experience debilitating anxiety and trauma as a result of abuse or neglect, or those who witness violence in their family or neighborhood.”

The policy recommendations of the working paper are:

  • The scientific understanding of how children cope with stress should be used to strengthen a range of informal supports and formal services to bolster parents who are struggling to manage the challenges of raising children.
  • High-quality early care and education programs that provide stable, supportive relationships with caring adults should be more available to young children who are at risk of experiencing tolerable or toxic stress.
  • Affordable expert assistance should be more available to parents, relatives, foster parents, teachers, physicians, caseworkers, and providers of early care and education who do not have sufficient knowledge and skills to help young children who exhibit symptoms related to abnormal stress response.
  • Existing intervention programs could better address the effects of toxic stress if they incorporate training and expertise in the identification of young children with serious, stress-related, mental health problems (as well as mothers with depression) and have ready access to expert assessment and mental health services as needed.
  • Responses to suspected child abuse or neglect should include an expert assessment of the child’s developmental status, including cognitive, linguistic, emotional, and social competence.
  • Because families experiencing poverty are likely to have greater exposure to stress and fewer resources to deal with adversity than the general population, adult-focused services…should be augmented to include developmental screening assessments for their children.  “Research also underscores the importance of timely assessments and intervention services (when indicated) for children living in stressful environments who show early signs of developmental difficulties.”