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The Science of Stress: How Does Stress Affect Young Minds?


Image credit: Kelly Sikkema


This week (1st-7th Feb, 2021) is Children’s Mental Health Week. This year, the event has special significance because it falls in the context of the pandemic that, as we know, experientially and through research, has far-reaching effects on the mental health of children, adolescents and their families.


Most of us have had some taste of the mental health knock-on effects of COVID-19, whether we grieved someone lost to COVID, struggled with the virus ourselves, experienced social isolation in lockdown, had anxiety, or, coped with new sources of stress.


This blog will take a look at some of the science of the effects of stress on young minds. As a researcher in child and adolescent mental health and a mother, I’m passionate about understanding the effects of stress on children and young people.


Over the past 6 years, I’ve been involved with a national programme called HeadStart that aims to increase children and adolescents’ wellbeing in six areas of England. My research has examined how young people experience stressors and the factors that they report to reduce their negative effects and help them cope, as well as how this changes over time.

As a parent that is working and home-schooling, I’m acutely aware that COVID-19 brings in new stressors for children and families, as well as new experiences and surprises.


COVID-19 Stressors

The COVID-19 pandemic has ushered in new stressors for everyone, and especially children and adolescents. Parents have been under more stress which can affect their children in both subtle and direct ways. Violence towards children increases during periods of crisis.


During the pandemic, children and young people have been exposed to new stressors, such as being away from the support of friends, school, teachers, extracurricular activities and community groups. Experiences of key worker children and children classified as vulnerable may be different from those that are at home with their families. In any case, children may also experience losing loved ones, worries about the risk of exposure, separation from grandparents and worrying about family health, parental employment, family poverty and uncertain futures. An increase in stressors can decrease both parents and children’s wellbeing.



Life in lockdown during COVID-19. Photo credit: Sharon McCutcheon


But what is a stressor and how does it affect the brain?



Stressors can be highly subjective. Some people may find wearing a mask stressful, for others, it is not stressful and simply a necessary behaviour change in the context of a pandemic. Or, to take another example, one person may love to take a flight in an airplane, whereas for others it is a highly stressful, anxiety-inducing experience. Thus, there is value in considering how stressors are subjectively perceived.


Stressor research often examines one stressor and its effect on mental health in isolation, such as the effects of bullying or domestic violence on health outcomes. Research often separates external stressors, such as features of the environment, from internal stressors, such as moods and states of emotions (for example, some studies only look at external stressors). However, in some qualitative research I undertook with adolescents in receipt of preventative mental health interventions, we found that stressors were not always neatly delineated in adolescent’s narratives and can be experienced in parallel.


When asking adolescents about the stressors they perceived, some young people described that both external and internal stressors were perceived interact to contribute to poor wellbeing and symptoms of a mental health disorder. An external stressor in the context of lockdown might include factors such as restrictions on meeting, or losing a job . An internal stressor might include worries about the risk of catching COVID or low mood from social isolation. Stressors can stack up and overwhelm, however.


What happens to the body and brain under stress?


The “fight and flight” response to stress occurs when the body has a physiological reaction to either run away from or fight a stressor (or freeze). Symptoms included increased heart rate, flushed cheeks, trembling and rapid breathing and more.


But is the fight and flight response problematic for young brains?


Fight or flight response found in humans and animals. Credit: Cloud Visual

Under normal (non-chronic) circumstances, stress is not damaging. The stress response triggers communication between the HPA (Hypothalamus-Pituitary-Adrenal) axis that increases and decreases in response to doses of stress. The stress hormone, cortisol, shuts down other systems (such as digestion) so that the body can focus on responding to a stressor. The releases of hormones enable a young person to be poised to respond to a stressor as indicated by rapid heartbeat and increased focus. After the threat has gone, the body returns to normal.


However, when stress occurs repeatedly over time, its chronicity alters the body’s resting state to a higher notch. The body stays primed in a state of anticipating constant threat and stress pathways become overactive. This serves to reduce the flexibility between an absence and presence of stress. When the load of stressors increases, a new set point is created, akin to increasing the thermostat on the body’s systems.



In this graph, the “set point” increases under stress, akin to a thermostat being turned up to a higher notch. Image credit: Lee, Kim & Choi, 2014


The cumulative weight of stressors on the brain is described as Allostatic Load (AL). Such a load of stressors are understood to overwhelm the balance of the body, described as allostasis. When the allostatic load becomes too great this contributes to “wear and tear” on the regulatory systems of the body and increases the risk of disease. Researchers can measure allostatic load by measuring biomarkers, such as waist circumference.


The effect of stress on the brain

Studies from rats and primates show that stress can alter the physical structures of the brain. Under stress, the body produces increased cortisol from the adrenal glands. The adrenal glands are triangular structures that sit on the top of the kidneys and regulate metabolism and the immune system. In the brain, raised levels of cortisol can change the size of the amygdala (an almond-shaped part of the brain linked to emotion and memory), and decrease the size of the hippocampus and specific dendrites that are part of the function of the prefrontal cortex.



Adolescence is a Sensitive Period of Brain Development

Research suggests that adolescence is a unique period of brain development described as a sensitive period. This means that the brain may be more influenced by the external environment during this time.



The adolescent brain is particularly sensitive to changes in the environment. Credit: Warren Wong


Research from both rodent and human studies suggests that the effects of drugs and peers are particularly strong during this time in a young person’s life. It is possible that the increased sensitivity of adolescents’ brains makes them more vulnerable to stress and developing mental health disorders. Many mental health disorders have their onset during adolescence. A review by Kessler and colleagues (2007) found that half of all lifetime mental health disorders begin by 14 years of age, but tend to be undetected and untreated.


Incredibly, not all children that are exposed to a stressor will experience poor outcomes later in adolescence or adulthood. Some children are resilient to the stressors they experience, they overcome them, others will not. The factors that contribute to resilience (and reduce the risk of mental health disorder) are described as protective factors. They include aspects such as a sense of humour and positive self-esteem. In addition to protective factors, there are other factors that result in differences in outcomes.


So given the damaging nature of stressors on the brain, what can be done about it? The power of emotions

Emotional support from parents and friends has the potential to counterbalance the negative effects of stress on the mind and body, research finds. The presence of emotional support from parents, friends and school can reduce the risk of mental health disorders and poor outcomes. According to the StressBuffering Hypothesis, if individuals perceive to be supported, this can reduce the negative effects of stressors on mental health or other outcomes.


The positive effects of emotional support on children. Credit: Juan Pablo Rodrigues


A study by Brody and colleagues (2014) found that rural African American children that had grown up in an area of poverty but received emotional support from their mothers had lower allostatic load than those that did not report emotional support.


When children (or adults) feel that they do not have the resources to manage a stressor that it exceeds their coping resources, this is highly problematic. Equally, if individuals feel that whilst a stressor is challenging they have the coping resources to manage it, this has found to have less of a negative effect on mental health.


We need to actively counter the effects of stress

Stressors have a profound influence on the minds of children and adolescents. Countering the effects of stressors on children, through interventions to reduce the negative effects of stress, are vital to protect and safeguard young people’s mental and physical health. As I understand it, it is important to put support in place for young people, that is based on evidence-based science (as not all types of support work for all young people) and it is important to understand what children and adolescents themselves report as stressor reducing and wellbeing enhancing. What makes young feel better both mentally and emotionally, can be highly individualised. Often (but fortunately not always!) one size fits all approaches don’t work to reduce the harmful effects of stress.


It’s likely that there is a lot of individual variation in what reduces stress for each of us Credit: James Lee


Next steps in terms of research


Some of my PhD research involved identifying patterns in a range of protective factors that adolescents themselves described as reducing the effects of stress and increasing their wellbeing. With colleagues at the Evidence Based Practice Unit, we have published a range of coping strategies described by adolescents to manage stress. Later this month, we will publish research on protective factors that are specific to children from minority ethnic groups. In the next few months of 2021, we aim to publish quantitative research examining the gender differences in trajectories of mental health and wellbeing that occur in early adolescence.


What are the future avenues in stress research for the wider field?

Here are three directions:

  1. Understanding the differential effects of stress

It is vital to understand how stress affects different social groups as a precursor to putting in place measures and interventions to alleviate stress. A recent piece of research has examined the different effects of stress and patterns of self-care across Latin American countries, genders and age groups.COVID has had differential effects on a range of social groups and it is well documented that BAME groups have been disproportionately affected (BIPOC in the US context). Understanding how stress affects various groups: young children, early adolescents, teenagers and young adults and how this intersects with factors such as race, class, nationality, geography, and sexual orientation is really important. It is important to understand minority stress and the specific challenges faced by people of colour as well as the ways that within the context of the pandemic, aspects of identity might increase vulnerability to stress or conversely, confer protection against it. It is important to consider the effects of COVID on groups that are suddenly thrust into poverty such as international students as well as service industry workers and other professions badly hit.


2. To investigate the role of technology and self-care in increasing or decreasing stress in the context of lockdown


A lot of support for mental health and wellbeing is mediated by technology, particularly for countries in lockdown. Children and adults spend more time on their phones and interacting with technology through online classrooms, Netflix, video games and online chat forms. Further research could examine how does technology reduce or increase stress on children and their parents during lockdown? Where there were previously clear boundaries between school and home, or work and home, what are the mental health effects of having fuzzier and looser boundaries and changed horizons as breaks in the school year are less pronounced. The family home under lockdown becomes a place of work, schooling, leisure, eating and sleeping, what does that mean for children’s mental health? Can children and teens get burnout?


Self-care can mitigate the negative effects of stress but the evidence base for self-care strategies is still in its’ infancy. In a 2019 systematic review of research evidence, only few self-care strategies had a strong evidence base of effectiveness to reduce anxiety and depression. Should adopting a self-care strategy (or encouraging a child to adopt one) be based on the subjective experience of its efficacy or the evidence base?


3. The links between stress and COVID related anger

Worldwide, throughout the pandemic, we have seen the rise of anger and externalising behaviours, whether in the form of resistance to masks, a group of Americans “storming the capitol”, the global rise in domestic violence, or public anger to changes and inconsistencies in COVID restrictions.


It would be immensely valuable to understand what exactly this increased anger means for mental health conditions, for children, their families and the longer-term effects on brain and behaviour and how this ties together with stress.


#ChildrensMentalHealthWeek is a brilliant time to get these conversations started. But it’s just as, if not more, important to keep these discussions going beyond this week, so that we can both understand and support every child as much as we can, every day.






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