Mr.

Tragic events like the shootings at Columbine High School capture public attention and concern, but are not typical of youth violence. Most adolescent homicides are committed in inner cities and outside of school. They most frequently involve an interpersonal dispute and a single victim. On average, six or seven youths are murdered in this country each day. Most of these are inner-city minority youths. Such acts of violence are tragic and contribute to a climate of fear in schools and communities.

Research findings are identifying factors in the development of aggressive and antisocial behavior from early childhood to adolescence and into adulthood. Prospective longitudinal and intervention studies have identified major correlates for the initiation, escalation, continuation, and cessation of serious violent offending.

Many studies indicate that a single factor or a single defining situation does not cause child and adolescent antisocial behavior. Rather, multiple factors contribute to and shape antisocial behavior over the course of development. Some factors relate to characteristics within the child, but many others relate to factors within the social environment (e.g., family, peers, school, neighborhood, and community contexts) that enable, shape, and maintain aggression, antisocial behavior, and related behavior problems.

The research on risk for aggressive, antisocial and violent behavior includes multiple aspects and stages of life, beginning with interactions in the family. Such forces as weak bonding, ineffective parenting (poor monitoring, ineffective, excessively harsh, or inconsistent discipline, inadequate super-vision), exposure to violence in the home, and a climate that supports aggression and violence puts children at risk for being violent later in life. This is particularly so for youth with problem behavior, such as early conduct and attention problems, depression, anxiety disorders, lower cognitive and verbal abilities, etc. Outside of the home, one of the major factors contributing to youth violence is the impact of peers. In the early school years, a good deal of mild aggression and violence is related to peer rejection and competition for status and attention. More serious behavior problems and violence are associated with smaller numbers of youths who are failing academically and who band together, often with other youth rejected by prosocial peers. Successful early adjustment at home increases the likelihood that children will overcome such individual challenges and not become violent. However, exposure to violent or aggressive behavior within a family or peer group may influence a child in that direction.

Types and Severity of Antisocial Behavior

The types and severity of antisocial behaviors exhibited by youths vary greatly and include lying, bullying, truancy, starting fights, vandalism, theft, assault, rape, and homicide. As a rule, the older the age of onset, the fewer the number of antisocial youths who will engage in seriously aggressive and violent behavior. Longitudinal studies show that many children who engage in antisocial behavior in childhood continue to do so at least through adolescence.

Longitudinal research has identified types of youth who progress to adolescent antisocial behavior, multiple pathways through which it develops and persists, and the multiple factors that shape this risk. This research has identified two types of life course trajectories: life course persistent, which is viewed as a form of psycho-

pathology, and adolescence limited, which is identified only in select social situations. The distinction between these two types of individuals is very useful, both as a way of thinking about developmental knowledge and as a tool for targeting the right interventions for antisocial youth.

Research in this area has generated evidence for this way of thinking about how adolescents grow and has investigated the relationship between adolescent problem behavior and cognitive deficits. Life course persistent individuals begin antisocial behavior early in childhood and continue into adulthood, after their adolescence limited counterparts stop. Life course persistent behavior has been correlated with neurological deficits and pathological behaviors, (e.g., impulsivity) which are exacerbated when they are combined with stressful home situations. In one study of 13 year olds, individual differences - such as deficits in sensory, perceptual, and cognitive abilities, including the use of languageC were shown to predict participation in crime five years later. For instance, boys with poorer verbal functioning initiated delinquent behavior at younger ages. It has also been demonstrated that boys with poorer neuropsychological functioning, especially verbal functioning at age 13, were more likely to have committed crimes at age 18 than were their counterparts with better neuropsychological functioning at age 13.

Gender Differences

From about 4 years of age on, boys are more likely than girls to engage in both aggressive and nonaggressive antisocial behavior. Much remains to be learned about the causes of gender differences in antisocial behavior, but based on what is known, it is suspected that antisocial behavior might need to be defined somewhat differently for the two genders. In contrast to overt aggression, which inflicts harm through physical damage or the threat of such damage more common in boys, social aggression by girls harms through damage to peer relationships; study of this form of aggression may be crucial to understanding the aggressive development of girls. The NIMH is currently funding research on the antecedents and consequences of aggression for girls, as well as for boys, knowledge that can be used to develop empirically-based interventions for aggressive children of both sexes.

Antisocial Behavior Co-Occurring with Child Psychopathology

There is strong evidence for the co-occurrence of two or more syndromes or disorders among children with behavioral and emotional problems. Many people think that children either act out or turn their feelings inward, but the truth is more complex. The obviously angry adolescent has other conditions such as anxiety disorders and depression (as seen in the quiet withdrawn young person) more often than would occur by chance. Research in this area indicates that very young children with conduct problems and anxiety disorders or depression display more serious aggression than youths with only conduct problems. It is not entirely clear whether depression precipitates acting out, whether impairments and predispositions for acting out lead to depression, or whether there are underlying causal factors