Early childhood is a critical period in a child's life that includes ages from birth to five years old.Poulsen, Marie K., and Karen M. Finello. "Foundations of Early Childhood Mental Health: Public Health & Life Course Perspectives." Preventive Medicine 583 Lecture. University of Southern California, Los Angeles. 25 Aug. 2011. Lecture.

Psychological stress In psychology, stress is a feeling of emotional strain and pressure. Stress is a form of psychological and mental discomfort. Small amounts of stress may be beneficial, as it can improve athletic performance, motivation and reaction to the envi ...

is an inevitable part of life. Human beings can experience stress from an early age. Although stress is a factor for the average human being, it can be a positive or negative molding aspect in a young child's life. A certain amount of stress is normal and necessary for survival. A few stressors can be manageable for young children; stress can be beneficial by helping children develop skills needed to adapt to a new set of circumstances and deal with dangerous and intimidating situations. Some experts have theorized that there is a point where prolonged or excessive stress becomes harmful and can lead to serious health effects. When stress builds up in early childhood, neurobiological factors are affected. In turn, levels of the stress hormone

cortisol Cortisol is a steroid hormone in the glucocorticoid class of hormones and a stress hormone. When used as medication, it is known as hydrocortisone. Cortisol is produced in many animals, mainly by the ''zona fasciculata'' of the adrenal corte ...

exceed normal ranges. This theory however is based on animal studies and cross-sectional studies in humans, and the proposed impacts on brain centers have not been found in a landmark twin study and studies where neurobiological factors were measured in humans prior to stress or trauma exposure. Researchers have proposed three distinct types of responses to stress in young children: ''positive'', ''tolerable'', and ''toxic''. These labels are based on theorized differences in lasting physiological changes occurring as a result of the intensity and duration of the stress response. Stress is caused by internal or external influences that disrupt an individual's normal state of well-being. These influences are capable of affecting health by causing emotional distress and leading to a variety of physiological changes. Internal stressors include physiological conditions such as hunger, pain, illness or fatigue. Other internal sources of stress consist of shyness in a child, emotions, gender, age and intellectual capacity. Childhood trauma has lifelong impact. Exposure to

adverse childhood experiences Adverse childhood experiences (ACEs) include childhood emotional, physical, or sexual abuse and household dysfunction during childhood. The categories are verbal abuse, physical abuse, contact sexual abuse, a battered mother/father, household sub ...

can include separation from family, home violence, racial/ethnic disparities, income disparities, neighborhood violence, mental illness or substance use disorder of caregiver, physical/sexual abuse, neglect, divorce, a new home or school, illness and hospitalization, death of a loved one, poverty, natural disasters, and adults' negative discipline techniques (e.g. spanking). Additional external stressors include prenatal drug exposure, such as maternal methamphetamine use, other maternal and paternal substance abuse, maternal depression, posttraumatic stress and psychosis.

Levels of stress

Researchers have proposed three different levels of stress seen in children during early childhood; ''positive'', ''tolerable'' and ''toxic''. Positive stress is necessary and promotes resilience, or the ability to function competently under threat.Davies, Douglas. "Chapter 3: Risk and Protective Factors: The Child, The Family, and Community Contexts." Child Development, A Practitioner's Guide. 2nd ed. New York: Guilford Press. Print. Such stress arises from brief, mild to moderate stressful experiences, buffered by the presence of a caring adult who can help the child cope with the stressor. This type of stress causes minor physiological and hormonal changes to the young child; these changes include an increase in heart rate and a change in hormone cortisol levels. The first day of school, a family wedding or making new friends are all examples of positive stressors. Such experiences can promote healthy development within an environment of supportive relationships, giving children the chance to observe and practice healthy responses to stressful events. Tolerable stress comes from adverse experiences that are more intense in nature but short-lived and can usually be overcome. The body's stress response is more intensely activated due to severe stressors. Some examples of tolerable stressors are family disruptions, accidents or a death of a loved one. It is important though to realize that such stressors are only tolerable when managed the correct way. Tolerable stress can turn into positive stress. With appropriate care from adults, young children can easily cope with tolerable stress and turn it into positive stress. However, if adult support is deficient in a child's coping stages, then tolerable stress can become detrimental. Toxic stress can occur when experiences are long in duration and intensity. Children need caring and supportive adults to help them because it is difficult for children to handle this type of stress on their own. Therefore, the stress response may be activated from weeks to months or even years. Prolonged stress leads to adverse effects such as permanent emotional or developmental damage. If sufficient support is not available, this type of stress can result in permanent changes in brain development. Research has found that children experiencing severe and long-term abuse have smaller brain sizes. If the situation is not as severe, toxic stress will still alter the stress response system; these changes will cause children to react to a wider variety of stressors. However, with sufficient care and support from adults, children can return their stress levels to tolerable or good. Examples of toxic stress are abuse, neglect, violence and overall hardship without adult support. Toxic stress can have a cumulative effect on physical and mental health.

Allostatic load Allostatic load is "the wear and tear on the body" which accumulates as an individual is exposed to repeated or chronic Stress (biology), stress. The term was coined by Bruce McEwen and Eliot Stellar in 1993. It represents the physiological conseq ...

is "the wear and tear on the body" that accumulates as an individual is exposed to repeated or chronic stress. It represents the

physiological Physiology (; ) is the science, scientific study of function (biology), functions and mechanism (biology), mechanisms in a life, living system. As a branches of science, subdiscipline of biology, physiology focuses on how organisms, organ syst ...

consequences of chronic exposure to fluctuating or heightened neural or

neuroendocrine Neuroendocrine cells are cells that receive neuronal input (through neurotransmitters released by nerve cells or neurosecretory cells) and, as a consequence of this input, release messenger molecules ( hormones) into the blood. In this way they b ...

response that results from repeated or chronic toxic stress. The term was coined by Bruce McEwen and E. Stellar in 1993.

Stages of stress

Stress is encountered in four different stages in early childhood. In the first stage, stress usually causes alarm. Next, in the second or appraisal stage, the child attempts to find meaning from the event. Stage three consists of children seeking out coping strategies. Lastly, in stage four, children execute one or more of the coping strategies. However, children with lower tolerance for stressors are more susceptible to alarm and find a broader array of events to be stressful. These children often experience chronic or toxic stress.

Causes

In the US, non-white children from a lower socioeconomic status are more prone to exposure to

. Black children from a lower socioeconomic status in particular are most at risk for exposure to adverse childhood experiences. Socioeconomic status can be measured by education and income level. A chronic exposure to stress will lead to the decline of physical health and increase susceptibility to diseases. Situations that may promote stress in childhood include:Tennant, V. (2005). School of Education at Johns Hopkins University-The Powerful Impact of Stress. Johns Hopkins School of Education - Home. Retrieved February 2013, from http://education.jhu.edu/PD/newhorizons/strategies/ topics/Keeping%20Fit%20for%20Learning/stress.html. * Loss of caregiver attachment: Divorce/separation, foster care, parental incarceration * Lack of attention * Racism * Separation from parents * Exposure to violence: physical, mental and

sexual abuse Sexual abuse or sex abuse is abusive sexual behavior by one person upon another. It is often perpetrated using physical force, or by taking advantage of another. It often consists of a persistent pattern of sexual assaults. The offender is re ...

Substance abuse Substance misuse, also known as drug misuse or, in older vernacular, substance abuse, is the use of a drug in amounts or by methods that are harmful to the individual or others. It is a form of substance-related disorder, differing definition ...

* Being over-scheduled * Feeling pressured to perform or behave beyond their ability *

Neglect In the context of caregiving, neglect is a form of abuse where the perpetrator, who is responsible for caring for someone who is unable to care for themselves, fails to do so. It can be a result of carelessness, indifference, or unwillingness and ...

: emotional and physical neglect * Meeting new people * Starting a new school * Death of a loved one * Illness: mental and physical * Difficulty with school work * Increased pressure/responsibility at home * Being bullied

Stress and brain development

Brain circuits and testosterone's systems are formed and activated in early life. These neurobiological systems of the body help maintain viability and are necessary for survival in early childhood and along the course of life.Gunnar, Megan, and Karina Quevedo. "The Neurobiology of Stress and Development."Advance (2007): 145–65. Annual Reviews. Web. 8 October 2011. . When a child or adult experiences a stressor, the body will attempt to regulate the stress through releasing hormones that pass through the body. However, effects of the prolonged or frequent biological stress response may increase the risk for future physical and mental health problems in early childhood. Since brain circuits are vulnerable in early childhood, early stressors may impact the development of necessary brain connections. Therefore, the theory of toxic stress is that stress might alter or impair brain circuit formation and essentially result in a small brain size in young children. There are however no studies yet that have measured these brain circuits or volumes of brain centers prospectively in young children to prove this theory.

Stress response pathway in humans

In humans, the stress response pathway consists of the sympathetic-adrenomedullary (SAM) system and the hypothalamic-pituitary-adrenal axis (HPA). The SAM system is a part of the sympathetic component of the

autonomic nervous system The autonomic nervous system (ANS), sometimes called the visceral nervous system and formerly the vegetative nervous system, is a division of the nervous system that operates viscera, internal organs, smooth muscle and glands. The autonomic nervo ...

. These systems are responsible for releasing

epinephrine Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions (e.g., respiration). It appears as a white microcrystalline granule. Adrenaline is normally produced by the adrenal glands a ...

and

norepinephrine Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic compound, organic chemical in the catecholamine family that functions in the brain and human body, body as a hormone, neurotransmitter and neuromodulator. The ...

(NE), also known as the

flight or fight response The fight-or-flight or the fight-flight-freeze-or-fawn (also called hyperarousal or the acute stress response) is a physiological reaction that occurs in response to a perceived Psychological trauma, harmful event, Trauma (medicine), attack, or t ...

hormones. When epinephrine is released it will bind to various receptors in various target organs; this will exhibit multiple roles in the fight or flight mechanism. The HPA system is responsible for producing glucocorticoids from the

adrenal cortex The adrenal cortex is the outer region and also the largest part of the adrenal gland. It is divided into three separate zones: zona glomerulosa, zona fasciculata and zona reticularis. Each zone is responsible for producing specific hormones. I ...

; the main

glucocorticoid Glucocorticoids (or, less commonly, glucocorticosteroids) are a class of corticosteroids, which are a class of steroid hormones. Glucocorticoids are corticosteroids that bind to the glucocorticoid receptor that is present in almost every vertebra ...

in humans is the steroid hormone cortisol. In contrast to epinephrine, which takes a short amount of time for production, cortisol takes up to 25 minutes to reach peak levels. Also, cortisol is able to penetrate the brain through the blood–brain barrier, unlike epinephrine. Therefore, cortisol takes more time to form, but impacts the brain for a longer period of time. In conjunction, the SAM and HPA systems work to regulate stress and unite at the

hypothalamus The hypothalamus (: hypothalami; ) is a small part of the vertebrate brain that contains a number of nucleus (neuroanatomy), nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrin ...

, which in turn regulates behavior.

Infancy, early childhood, and stress

When the body undergoes a stressful situation, the stress hormone

is released. Cortisol helps the body prepare for stressful and dangerous situations. It gives a quick burst of energy, heightened memory and lower sensitivity to pain, among other things.Cortisol and Stress: How Cortisol Affects Your Body, and How To Stay Healthy in the Face of Stress. Stress and Stress Management - Causes, Symptoms, Stress Relief Tips and Stress Tests. Retrieved from http://stress.about.com/od/stresshealth/a/cortisol.htm. When cortisol is present in the body at high levels and for extended periods of time, however, the body's immune response may be suppressed. This leaves the developing bodies of children extremely vulnerable to damage and illness. Cortisol is usually bound to proteins in adults. The protein is called the corticosteroid-binding globulin (CBG). In newborn babies, CBGs remain low and increase during the first six months after birth. Therefore, as the amount of CBGs increase, more cortisol becomes bound to the CBGs. Due to this occurrence, plasma and total cortisol levels increase. Although there are low levels of cortisol at birth, the levels are sufficient to have serious physiological effects. Newborns do not manifest typical adult circadian rhythms in cortisol production. Usually, newborns have peak cortisol levels every 12 hours and this does not depend on the time of day. After three months of life, babies begin to experience the adult cortisol production patterns, an early morning cortisol peak and low evening levels of cortisol. These cortisol rhythmic changes occur throughout infancy and early childhood, along with changes in sleep patterns. The activity of the HPA stress system adapts by repeated exposure to stressful stimulation. As newborns progress through the early months of life, babies experience increased cortisol levels during medical examinations. This is physically characterized by the fussing and crying of babies. After three months of life, babies do not respond to physical examinations with the HPA stress response system. However, babies can still respond to behavioral distress. As another example, if blood is drawn from a baby, the baby experiences an increased cortisol level. When this process is repeated 24 hours later, the same increase in cortisol is observed. In addition, during the first year of life, it becomes difficult to induce cortisol level increases to some mild stressors. These stressors include the approach of a stranger, strange events, few-minute separations from parents, and more. The decreased sensitivity of the HPA stress response may be due to physiological changes that occur in the system during early ages. The physiological changes that may occur include improved negative feedback regulation of the HPA system, and decreased sensitivity of the adrenal cortex to ACTH. Also, the availability of adult support for young children helps safeguard the activity of the HPA stress system. The effects of repeated increases in cortisol levels have been researched in many animal studies, but these types of controlled studies are not ethical to conduct in humans. It has been determined that when glucocorticoids, including cortisol, are placed into various parts of rats' brains for many days, CRH is produced in increased quantities. In turn, this causes fear behaviors, increased caution, and activation of competing regulatory systems. The hypothesized mechanism of action that causes permanent damage in the toxic stress theory is that excessive levels of cortisol may cause neuronal cell death, particularly in the hippocampus, which has relatively high levels of glucocorticoid receptors. Because children's brains are developing relatively more compared to later in life, there is concern that their brains might be relatively more vulnerable to stressors compared to adults. Research has shown that children who have experienced extended periods of extreme stress have smaller brains. Children who had experienced more intense and lasting stressful events in their lives posted lower scores on tests of spatial working memory. They had more trouble navigating tests of short-term memory as well. The region of the brain that is most affected by increased levels of cortisol and other glucocorticoids is the

hippocampus The hippocampus (: hippocampi; via Latin from Ancient Greek, Greek , 'seahorse'), also hippocampus proper, is a major component of the brain of humans and many other vertebrates. In the human brain the hippocampus, the dentate gyrus, and the ...

. Research has found that infants and young children with higher cortisol levels produce smaller electrical changes in their brain when they are forming memories. This impairs new memory formation. In addition, children who have increased levels of cortisol, during daycare or nursery school time, experience extreme hardship upholding attention. Maintaining attention is a part of self-regulation, and these children are not able to regulate their behaviors due to the high cortisol levels. Therefore, memory, attention-span, and self-regulation are influenced by cortisol production. Despite the concerns about the impact of stress and cortisol on developing brains, the existing data are inconsistent. Some children manifest low levels of cortisol production under stress, and some experience high cortisol levels. While one concern is that children with higher levels of glucocorticoids may be prone to have the most problems with physical, social, mental, and motor development, research has neither determined whether these effects are permanent, nor whether these associations would hold up under more rigorous prospective studies.

Toxic stress

Toxic stress is a term coined by pediatrician Jack P. Shonkoff of the Center on the Developing Child at

Harvard University Harvard University is a Private university, private Ivy League research university in Cambridge, Massachusetts, United States. Founded in 1636 and named for its first benefactor, the History of the Puritans in North America, Puritan clergyma ...

to refer to chronic, excessive stress that exceeds a child's ability to cope, especially in the absence of supportive caregiving from adults. According to Shonkoff, extreme, long-lasting stress in the absence of supportive relationships to buffer the effects of a heightened stress response can produce damage and weakening of bodily and brain systems, which can lead to diminished physical and mental health throughout a person's lifetime. Extreme exposure to such toxic stress can result in the stress response system becoming more highly sensitized to stressful events, producing increased wear and tear on physical systems through over-activation of the body's stress response. This wear and tear increases the later risk of various physical and mental illnesses.

Other symptoms and effects of stress on children

Physical

Stress may make the

body Body may refer to: In science * Physical body, an object in physics that represents a large amount, has mass or takes up space * Body (biology), the physical material of an organism * Body plan, the physical features shared by a group of anim ...

more susceptible to infections, cardiovascular problems such as

heart disease Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina pectoris, angina, myocardial infarction, heart attack), heart failure, ...

and high blood pressure,

obesity Obesity is a medical condition, considered by multiple organizations to be a disease, in which excess Adipose tissue, body fat has accumulated to such an extent that it can potentially have negative effects on health. People are classifi ...

, slower healing, viruses and gastrointestinal problems.WebMD. Stress Symptoms: Effects of Stress on the Body. WebMD - Better information. Better health. Retrieved from http://www.webmd.com/balance/stress-management/stress-symptoms-effects_of-stress-on-the-body. Stress can affect children's growth and development, including the onset of

puberty Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a female, the testicles i ...

. Some of the physical cues that may be indicative of stress in children are rashes on skin and skin diseases such as

eczema Dermatitis is a term used for different types of skin inflammation, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened ...

acne Acne ( ), also known as ''acne vulgaris'', is a long-term Cutaneous condition, skin condition that occurs when Keratinocyte, dead skin cells and Sebum, oil from the skin clog hair follicles. Typical features of the condition include comedo, ...

and

hair loss Hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body. Typically at least the head is involved. The severity of hair loss can vary from a small area to the entire body. Inflammation or scarring ...

, worsening

asthma Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wh ...

, insomnia or hypersomnia, frequent headaches, muscle aches, vomiting, constipation and diarrhea. Extreme fatigue, chest pain, racing heartbeat, shaking, cold and clammy hands and feet, frequently ill, and even

ulcers An ulcer is a discontinuity or break in a bodily membrane that impedes normal function of the affected organ. According to Robbins's pathology, "ulcer is the breach of the continuity of skin, epithelium or mucous membrane caused by sloughing ...

are some other physical symptoms manifested due to stress.

Emotional

When children cannot handle stress they may begin to develop emotional problems. They may become severely depressed, lacking in energy and motivation. They may develop strange personality traits such as violence and disobedience. Personality disorders may arise as well. Posttraumatic stress disorder may come about in children who have experienced stressors that are traumatic such as abuse or neglect.PTSD in Children. Dendrite Forest, Inc. Retrieved from http://www.forests.com/ptsdchil1.html.

Psychological

Changes in mood or personality, increased irritability or aggressiveness are some psychological symptoms indicative of stress in children. Frustration, feelings of guilt or confusion, isolating themselves from family and friends. Children may also exhibit symptoms of

anxiety Anxiety is an emotion characterised by an unpleasant state of inner wikt:turmoil, turmoil and includes feelings of dread over Anticipation, anticipated events. Anxiety is different from fear in that fear is defined as the emotional response ...

. They may begin to have new fears and nightmares or even paranoia. 9They may lie to others to avoid situations to cover up their feelings. Most often anxiety in children stems from academic stressors and being overwhelmed with responsibilities with workload.

Social

Children under extreme stress tend to withdraw from their family and friends. They spend more time alone and lack motivation. Children may begin to struggle in school and on their assignments.Children and Stress: Caring Strategies to Guide Children - Home - Virginia Cooperative Extension. Publications and Educational Resources - Home – Virginia Cooperative Extension. Retrieved from http://pubs.ext.vt.edu/350/350-054/350-054.html. They may have difficulties in paying attention and act with anger and irritability towards others.

Behavioral

Children may exhibit behavioral symptoms such as over-activity, disobedience to parental or caretaker's instructions. New

habits A habit (or wont, as a humorous and formal term) is a routine of behavior that is repeated regularly and tends to occur subconsciously. A 1903 paper in the ''American Journal of Psychology'' defined a "habit, from the standpoint of psychology, [ ...

or habits of regression may appear, such as thumb-sucking, wetting the bed and teeth grinding. Children may exhibit changes in eating habits or other habits such as biting nails or picking at skin due to stress. They may become more accident-prone, cry more often, stutter, or get into fights.

Long-term effects of stress on children

The landmark Adverse Childhood Experiences Study (ACE Study) conducted between 1995 and 1997 on 17,337 participants by Dr. Vincent Felitti from the Kaiser Permanente health maintenance organization and Dr. Robert Anda from the Centers for Disease Control and Prevention demonstrated the association of adverse childhood experiences (ACEs) with health and social problems as an adult. Participants were asked about the following types of childhood trauma: * Physical abuse *

Sexual abuse Sexual abuse or sex abuse is abusive sexual behavior by one person upon another. It is often perpetrated using physical force, or by taking advantage of another. It often consists of a persistent pattern of sexual assaults. The offender is re ...

* Emotional abuse * Physical neglect * Emotional neglect * Violent treatment from mother * Household

substance abuse Substance misuse, also known as drug misuse or, in older vernacular, substance abuse, is the use of a drug in amounts or by methods that are harmful to the individual or others. It is a form of substance-related disorder, differing definition ...

* Household

mental illness A mental disorder, also referred to as a mental illness, a mental health condition, or a psychiatric disability, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. A mental disorder is ...

* Parental separation or

divorce Divorce (also known as dissolution of marriage) is the process of terminating a marriage or marital union. Divorce usually entails the canceling or reorganising of the legal duties and responsibilities of marriage, thus dissolving the M ...

* Incarcerated household member The ACE study found that ACEs have a

dose–response relationship The dose–response relationship, or exposure–response relationship, describes the magnitude of the Stimulus–response model, response of an organism, as a Function (mathematics), function of exposure (or Dose (biochemistry), doses) to a Sti ...

with many health problems. As researchers followed participants over time, they discovered that a person's cumulative ACEs score has a strong, graded relationship to numerous health,

social Social organisms, including human(s), live collectively in interacting populations. This interaction is considered social whether they are aware of it or not, and whether the exchange is voluntary or not. Etymology The word "social" derives fro ...

, and behavioral problems throughout their lifespan, including substance use disorders. Furthermore, many problems related to ACEs tend to be

comorbid In medicine, comorbidity refers to the simultaneous presence of two or more medical conditions in a patient; often co-occurring (that is, concomitant or concurrent) with a primary condition. It originates from the Latin term (meaning "sicknes ...

, or co-occurring.

Notes

{{reflist, 30em Child and adolescent psychiatry Stress (biological and psychological)