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.