Thinking About Violence in Our Schools

Child and Adolescent Violence Research at the NIMH

Helping Children and Adolescents Cope with Violence and Disasters

Thinking About Violence in Our Schools

Introduction

Violence in our schools is not a simple problem with a single cause. There are many influences or events that can set a child onto a negative trajectory that for some children, ends tragically. Over the last year, with the leadership of the First Lady, Hillary Rodham Clinton, we have been able to highlight research on early childhood and brain development for the nation. An understanding of the timing of brain development, and the types of environments in which it can proceed on a healthy trajectory have important policy implications. This awareness is a very important beginning on which we should build. For example, we know that brain development continues throughout childhood and adolescence, but for success in school and in life, we need to pay attention not only to cognitive development, but also to emotional development. The negative effects of neglect and abuse, poor adult supervision, and the influence of deviant peers and of exposure to violence are important, but have been well documented; less well understood are the emotional disorders of childhood that may lead to the violence that seems to "come out of nowhere." The causes of this violence; indeed the reasons for the frequency of depression and other emotional disturbances in our society are complex and not fully understood.

So today, I would like to focus on brain development in the context of the emotional development of children. Hopefully, this broader view of emotion can inform a discussion of violence. It is striking that as I read the popular press and the education literature, the fundamental emphasis with regard to brain development is on the cognitive aspects. This is important to be sure, but the emotional side of development often goes unattended. Surely, however, a child with difficulties in the arenas of emotion and motivation cannot benefit cognitively to the fullest degree from even the best educational programs. Indeed, when we worry about emotional development, it is most often for the subset of children with disruptive behavior, not the "quiet child" who may be suffering.

Over the course of recent history there have been many approaches recommended to the "moral education" of children. I would argue, and many might agree, that these approaches have represented more a succession of schools of thought, often on the subject of discipline than a cumulative scientific enterprise. Perhaps it comes as a surprise, however, that we have a dearth of really good science in the identification and treatment even of conditions of childhood that deserve to be called mental disorders. We still have an inadequate ability to distinguish the early symptoms of disorders that portend serious life-long difficulties from still serious, but transient dysfunction. The problems of appropriate recognition and intervention are particularly acute in pediatric primary care settings, where for example perhaps only 25% of children with clinical depression are recognized. Even when such conditions are recognized there is often insufficient information available about treatment. We have few well validated psychosocial approaches to children with depression or anxiety disorders, for example. We know more about diagnosis and treatment of attention deficit disorder, but not enough. As in other areas of child health, we have little specific knowledge about the safety and efficacy of psychotherapeutic drugs in childhood, a lack that denies rational treatment to our children. Thus some children disabled by disorders of mood or anxiety are left untreated; at the same time we continue to have deep concerns for those who are treated, about the long-term effects of psychotropic drugs on the developing brain. The point has been made many times, but remains critical: children are not simply small adults. In the case of both psychotherapeutic drugs and psychotherapies different stages of brain development and changing handling of drugs by the body means that specific developmentally appropriate information is needed about infants, toddlers, school-age children, and both early and late adolescents. Fortunately, the research community is beginning to establish pediatric testing of drugs.

What does this mean? Children with unrecognized or untreated emotional disorders, even those that might be transitory, are put at high risk for being unable to live up to their potential in both family life and work life. Children with these disorders, regardless of their intellectual ability, cannot learn adequately at school or readily form the kinds of healthy peer and family relationships that undergird the emergence into adulthood of healthy and productive citizens. Children thus derailed from a healthy emotional trajectory are at heightened risk for school failure and dropout, drug use, risky behaviors, including the risk of HIV transmission, and violence.

Brain development

The process of brain development borders on the miraculous. More than 100 billion cells must migrate to the right position in the developing brain and must, in aggregate, make a quadrillion connections with each other, some over remarkably long distances. These nerve cells must also establish the right biochemical identity in order to produce the right repertoire of the hundred or more chemicals that nerve cells in the brain release in order to signal to each other and the many hundreds of receptors that permit them to respond to the chemical messages sent by other cells.

While it is true that a single defective gene may cause certain devastating brain disorders such as Huntington's disease or in some cases, Parkinson's disease, normal emotional and cognitive development and vulnerability to emotional disorders is the work of a large number of genes, most likely acting in different parts of the brain at different stages of development. Perhaps two thirds of the genes in the human genome are involved either in building the brain or in its adult functioning.

A profound truth that we have learned about brain development and vulnerability to mental disorders is that as complex as the gene-gene interactions are proving to be, they do not explain everything: equally complex gene-environment interactions are also involved. The interaction of genes and environment permit the limited information in the genome to be read out in such as way as to produce the human brain. Our brains have been described as the most complex structure in the known universe, and complex they must be to confer on humanity its wonderful richness and diversity, and above all, to permit us to adapt to the many different environments and conditions in which human beings live. How might the environment cause our brains to develop in one possible way rather than another? Insofar as we experience it or interact with it, the environment produces biochemical changes in the nerve cells within our brains. When such biochemical changes are of large enough magnitude, they turn genes on and off inside those cells as part of normal processes that go by the name of brain plasticity. These physical changes caused by experience within the brain are the basis of all long-term memory. During development, as these little tweaks add up, our brains get wired up one way or another. This has sometimes been described as "sculpting" the brain. This sculpting occurs, of course, by the regulation of genes by the environment, which not only builds new connections but also may eliminate connections that go unused.

The area in which we know most about plasticity in development is the visual system. Genes are largely responsible for the initial wiring up of the brain. Nerve fibers from the retina, the membrane at the back of the eye which is the receiving surface for the visual world, make the long journey to a way station in the middle of the brain, and from there another set of fibers make the journey to the very back of the brain, the primary visual cortex. There preliminary connections are set up, but the fine tuning is dependent not simply on genes, but on use. As light excites nerve cells in the retina and they signal to the brain, those connections or synapses that are used effectively are strengthened and maintained. Those that are not used are pruned away. A condition that occasionally arises in children is a congenital cataract, an opacity that blocks light from entering the eye. It has been found that if such a cataract is removed, an optically perfect eye can be restored; but if the surgery does not occur early enough in childhood, before age 4, the child will not regain vision in that now normal eye. In the case of the developing visual system, there is a critical period during which the appropriate parts of the brain remain plastic. When that period comes to an end, the visual system is essentially fixed: incoming visual stimulation can no longer act to alter synaptic connections.

The information we have on brain development is no longer limited to sensory systems or cognition. In a series of experiments in a variety of labs it has been shown that if a rat pup is gently handled by an investigator, the mother licks the pup repeatedly when it is returned to her. Those handled pups have been found to have a less reactive stress hormone system throughout life than their littermates. Based on those results, rat mothers were observed for spontaneous licking of their pups. The pups from the dams that licked them most also proved to have less reactive stress hormone systems throughout life, even without the intervention of the investigator. This is evidence of the importance of nurturing on the development of physiological systems as the brain matures.

As we move to the somewhat more speculative arena, we can ask how abuse or neglect might alter emotional development by changing the brain. A structure in the brain called the amygdala, which is about the size of an almond, found deep within the temporal lobes, is required for the processing of fear and for laying down emotional aspects of memory. It appears that the amygdala matures earlier than the hippocampus, a structure required for explicit conscious memories. Thus the emotional and physiologic aspects of abuse, neglect, or even less dramatic, but nonetheless, negative situations, may be recorded indelibly in a child's brain before the child has any narrative memories of life.

We must also recognize that some emotional conditions may occur without any apparently negative experiences. When, for example, there is strong genetic loading, a child may begin to exhibit depressive symptoms even without salient negative experiences. These cases are more subtle than those in which we can identify environment factors such as abuse. They are also more problematic. Parents may feel inappropriately ashamed when their children have emotional symptoms. They may find themselves blamed by other family members or by their pediatrician. However, untreated depression or attention deficit disorder creates its own malign plasticity. A congenital cataract that is neglected and leaves a child blind is now an avoidable tragedy. Less well understood than cataracts, but far more common, are the unrecognized or still untreated or untreatable mental disorders of childhood, or situations of abuse and neglect. These situations also impact the developing brains of our children with devastating consequences.

We need more research certainly, for as I stated at the beginning--we are far from possessing satisfactory knowledge about how to proceed, but we already have enough knowledge to do a far better job than we are doing. We could do more to educate parents, teachers, guidance counselors, pediatricians and school psychologists to take notice of the early warning signs. We could teach them to look for the quiet child as well as the one who is more obviously in trouble. We must correct the sense of stigma and shame that inappropriately causes so many families to suffer in silence with potentially devastating consequences. When we think of the developing brain we should think not only of cognitive, but also of emotional development.

America needs to have a discussion about the needs of children. We should take the opportunities that arise from these tragedies to make a difference. We need to test proposed interventions, whether psychosocial or pharmacologic, for efficacy and lack of side effects for anything that is powerful enough to make a difference is powerful enough to cause untoward effects. We must work arm-in-arm with research and put together a group of the best scientists to help pediatricians, families, communities and schools to recognize emotional disturbance and to evaluate treatment strategies. We need to acknowledge the special rapidly changing nature of childhood and learn to time psychosocial and medication therapies in line with the perspective that these are critical periods in brain development.

Steven E. Hyman, M.D.
Director, National Institute of Mental Health

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