glucocorticoids is the hippocampus. 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 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 more susceptible to infections, cardiovascular problems such as heart disease and high blood pressure, obesity, slower healing, viruses and gastrointestinal problems. stress can affect children's growth and development, including the onset of puberty. some of the physical cues that may be indicative of stress in children are rashes on skin and skin diseases such as eczema, acne and hair loss, worsening asthma, 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 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. psychological main article: psychological stress § psychological stress and disease 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. they may begin to have new fears and nightmares or even paranoia. they 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 main article: social stress 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. 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 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 main article: adverse childhood experiences study the ace pyramid represents the conceptual framework for the ace study, which has uncovered how adverse childhood experiences are strongly related to various risk factors for disease throughout the lifespan, according to the centers for disease control and prevention. 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 emotional abuse physical neglect emotional neglect violent treatment from mother household substance abuse household mental illness parental separation or divorce incarcerated household member the ace study found that aces have a dose–response relationship 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, and behavioral problems throughout their lifespan, including substance use disorders. furthermore, many problems related to aces tend to be comorbid, or co-occurring.