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Biology 202
2001 Third Web Report
On Serendip
Wendy's assessment of the situation is correct-all children must grow up. Or do they? Most of the time, children do grow up. They become adults. They live their lives. There are not many Peter Pans out there who refused to grow up and succeed. However, in some extremely rare cases, stress prevents children from growing. If you are short, you may be thinking that perhaps you suffered from this type of stress and you did not grow to your full potential. Perhaps your parents divorced, or you moved around frequently. This kind of stress, nevertheless, is not severe enough to prevent a child from growing. Rather, those who suffer from this disorder are the children who are extremely neglected (mistreated in orphanages, locked in rooms, completely neglected). The result is an extremely rare disease known as psychogenic or psychosocial dwarfism. What are the causes of this rare disease? How much is biological and how much is social? Why is it that stress can have such a profound effect on the bodies' normal development and maintenance?
One disturbing case of psychogenic dwarfism is the story of a wealthy British Victorian family who experienced the loss of the mother's favorite 13-year-old son, David, in a skating accident. The mother, extremely distressed about her loss, never recovers and subsequently ignores her other, six-year old son. Upon entering the room to see his mother, the boy is met with "David, is that you? Could it be you?" and when she realizes that it is her other son, exclaims "Oh, it's only you." When the mother does speak to her son, it is only to say that at least David died as a perfect boy who would always need his mother. As a result of extreme neglect, (the father did not interact with the children) and perhaps psychological abuse, this son stops growing and never reaches puberty. As an adult he is 4'10". The surprising end to this story is that this "man" "grew up" to be the author of the beloved story-Peter Pan, J.M. Barrie, who was forever writing about boys who did not grow up (2).
Psychogenic dwarfism is a growth disorder that is observed between the ages of 2 and 15, caused by extreme emotional deprivation. The symptoms include decreased growth hormone (GH) secretion, very short stature, weight that is inappropriate for the height, and immature skeletal age. This disease is a progressive one, and as long as the child is left in the stressing environment, his or her cognitive and linear abilities continue to degenerate (3).
One of the major underlying commonalities among these children is the extremely low level of growth hormone. In a normal person, these growth hormones are secreted by the pituitary gland and are regulated by the hypothalamus. It involves a hormone that stimulates growth-growth hormone releasing hormone (GHRH) and one that inhibits release-growth hormone inhibiting hormone (GHIH). In children with psychogenic dwarfism, there may be a problem with the hypothalamus-either too little GHRH or too much GHIH, or perhaps a combination of both. While difficult to study in humans, animal studies indicate that the problem most likely lies in too much GHIH. In addition, the hypothalamus may be acting differently in these children by being too sensitive to GHIH or unresponsive to GHRH (4).
When this hormone is secreted, it binds along with somatomedins to receptors in the target cells, stimulating growth. In addition to the hypothalamic insensitivity present in psychogenic dwarfism, these target cells may become unresponsive to the growth hormones. A study by Cynthia Kuhn and Saul Schanberg studied an enzyme essential to cell division called ornithine decarboxylase (ODC) in rats. If the infants were taken away from their mothers, the growth hormone levels and ODC levels deteriorated. If the rats were then injected with growth hormones, ODC levels still did not reach adequate amounts (5). This indicates that the maternal deprivation was the cause of the ODC degeneration.
The sympathetic nervous system is also involved. An excessively active sympathetic nervous system may inhibit growth hormone secretion. Researchers have attempted to pinpoint the importance of this factor in psychogenic dwarfism by injecting a drug that blocks one part of the sympathetic nervous system. Studies have indicated that this causes an increase in growth hormone levels that eventually return to normal. Additionally, glucocorticoids play a factor. Glucocorticoids are steroid hormones that act similarly to epinephrine and serve to energize the body during periods of stress; however, unlike epinephrine that acts within seconds, glucocorticoids work over a period of hours. This suggests that perhaps glucocorticoids act to help the body recover after a stressor, or prepare for the next stressor, rather than mediating the stress response (5). Not surprisingly, some children with psychogenic dwarfism display high levels of glucocorticoids. This effect is also seen in rats that have been deprived of their mothers. Glucocorticoids block the secretion of the growth hormone, the reception of growth hormones by the target cells, and the synthesis of new proteins and new DNA in dividing cells (6).
In cases of extreme stress, for example, running from an animal that is trying to kill you, your body reacts in certain ways in order to optimizes your chances for survival. The hypothalamus becomes hyperactivated, which activates the pituitary gland, releasing adrenocorticotrophic (ACTH), into the blood, which in turn activates the adrenal glands to prepare for fight or flight. The digestive, immune, and reproductive systems shut down as not to expend unneeded energy. Stress also shortens cognition and enhances sensory sensitivity. Stress also increases heart rate and the cardiovascular system, so that the person can run away faster. Energy is mobilized for immediate use; however, this prevents the person from storing energy. These effects are all extremely important when the danger is imminent and the stress short-lived. Prolonged stress, however, is extremely detrimental to the health of a person. The person is always tired because energy is not stored for later use. Neurons die as a result of the same hormones that increase cognition. In addition, the growth systems shut down. It is beneficial to the body not to expend energy on repairing bones or stimulating growth hormones while being chased by a lion. Therefore, the body stops these processes in times of stress, and in a normal person, resumes growth activity after the danger is over (7).
Children who suffer from psychogenic dwarfism, however, are in a constant state of stress. In addition to suffering from the effects of little to no growth hormones in their bodies, they also suffer severe gastrointestinal problems resulting from increased levels of epinephrine and norepinephrine. The result is that they are unable to reap the benefits of the nutrients they intake. Their bodies simply do not absorb the nutrients from the food ingested. Until they are removed from their stressful situations, their bodies refuse to take the necessary steps to behave normally. To their bodies, the children are still fleeing from the lion, and the body, therefore, behaves accordingly.
In addition to the story concerning the author of Peter Pan, there have been a variety of examples of psychogenic dwarfism observed in humans (8), as well as animal experiments attempting to explain this bizarre phenomenon. The most striking and common cases of psychogenic dwarfism are present in the study of orphanages in the mid-1900s. There were two orphanages studied right after WWII. One of was run by a very nurturing mother who comforted the children and spent hours a day with them. A woman who spent no time with the children and constantly belittled them ran the other orphanage. Based on the theories of psychogenic dwarfism, it is not surprising that the growth rates at the first orphanage were much higher than those of the second. In addition, when the woman who headed the second orphanage was transferred, the growth rates increased, while the ones at her new orphanage decreased. There is also the case of a severely dwarfed child whose progress was charted after his arrival to a hospital. A few months after his admittance, he became emotionally attached to a particular nurse. His progress soared. His growth hormone levels and rate of growth increased dramatically. The nurse, however, took a three-week vacation, and during this time, the child's growth hormone level and growth rate suddenly decreased to the levels he displayed upon entering the hospital. This happened despite the child maintaining the same levels of food intake. When the nurse returned, his levels returned to normal.
What specifically in this neglect causes psychogenic dwarfism? Is it the talking and encouragement? Or perhaps something else? There are human and animal studies that suggest that it is the lack of touch that results in the stunted growth. If rat pups are given contact with their anesthetized mother, or if baby monkeys are exposed to the sound of their mother's voice, their growth hormone levels are still low. However, if the rat pups are stroked (imitating active licking), growth hormone levels increase. Another experiment, involving human infants, indicated the same findings. Researches observed that premature babies, while well cared for, were rarely touched. The experimenters began touching and holding half of the infants. The results were striking. These handled infants grew 50 percent faster and were released earlier than those infants who were not handled by the researchers. In addition, these infants were also healthier months after their release when compared to the non-handled infants (5). These results indicate that contact is one of the major influences necessary for proper growth.
Some of the studies on psychogenic dwarfism indicate that emotional deprivation is the culprit. Other studies indicate that the major stressor is a result of the lack of touch. Which of these is the more important stressor? Or do both need to be present in order to initiate the psychogenic dwarfism? Imagine a child who is constantly held and touched by a mother who is nevertheless severely emotionally abusive. Is it possible that this child would also suffer from some sort of stress-induced dwarfism, even if not as severe as psychogenic dwarfism? What about the role of the mind in not wanting to grow? Certain disorders such as anorexia stem in part from a desire to escape adulthood. It is reasonable that conscious and unconscious desires affect the way the body grows. However, experiments identifying the exact causes of psychogenic dwarfism are extremely difficult both because of the rarity of the cases and because of the ethics involved in conducting human experiments-one cannot lock a child into a room for years to note the effects. The animal data, while consistent, cannot be definitively applied to humans. Nor can the case of one child be applied to the thousands of others who suffer from this horrible and debilitating disease. Since it is difficult to experimentally manipulate growth patterns of children, the orphanage data is often cited in the literature concerning psychogenic dwarfism. However, children in orphanages are exposed to a barrage of other stressors and influences that may affect their growth-aside from motherly deprivation. It is difficult, then, to reliably identify this data as conclusive.
Under stress, the body has the power to do extraordinary things in order to survive. Nowadays, however, we stress ourselves unnecessarily. It is rare that we are faced with a life or death situation necessitating the inactivation of the life systems indicated above. Nevertheless we give ourselves ulcers and heart attacks, kill neurons, and instigate other such incapacitating diseases because our minds tell our bodies that we are stressed. The mechanisms behind stress are currently being further studied as well as more effective ways of coping with our 20th century "life or death" stress situations (9). The implications of research surrounding psychogenic dwarfism as well as other stress-related disorders, can lead us to answer questions about what happens to our bodies in times of stress and how we can learn to manage our stress and calm ourselves down. While we may desire to stay young forever and live carefree in the neverland, stress is not the fairy dust necessary to go to the second star to the right and straight on 'till morning.
3) Physical Development in Early Childhood
4) Child Abuse & Neglect: Psychosocial Dwarfism from Pediatrics/Developmental & Behavioral
6) Experience can Influence Development
8) Psychosocial Dwarfism: A Closer Look
9) Killer Stress-and What to Do About It
5) Sapolsky, Robert M. Why Zebras Don't Get Ulcers: An Updated Guide to Stress, Stress-Related Diseases, and Coping. New York: W.H. Freeman and Company, 1998.
