Multiple factors contribute to and shape behavior over the course of adolescent behavior. Certain risk factors contribute to violent behavior while the existence of “protective” factors prevents violent behavior. Risk factors are defined as established determinants where there is strong objective evidence of a causal relationship to a problem. Protective factors are those that potentially decrease the likelihood of engaging in a risk behavior. The ecological model recognizes that each person functions within a network of individual, family, community, and environmental contexts that impact their capacity to avoid risk. Environmental factors, such as socioeconomic status and media exposure to violence, play an important role in creating conditions that contribute to a culture of violence among a particular group of people or in a given community. In addition, many youth find it difficult to engage in meaningful relationships with adults. Community level factors that contribute to the risk for youth violence include the availability of drugs and firearms, community deterioration or disorganization, and access to quality educational and recreational opportunities. A strong community infrastructure has been identified as a protective factor against youth violence. The lack of parental interaction and involvement increases the risk for violence, particularly among males. Failure to set clear expectations, inadequate youth supervision and monitoring, and severe or inconsistent family discipline practices can contribute to delinquency and violent behavior. Children or youth that have been physically abused or neglected are more likely than others to commit violent crimes later on. Exposure to high levels of marital and family conflict also appears to increase risk, as does antisocial or delinquent behavior by siblings and peers. In regard to individual factors, there is consistent evidence suggesting a correlation between violent behavior and hyperactivity, concentration problems, restlessness, and risk taking. There is strong evidence for the co-occurrence of mental health disorders, such as depression, among children or youth with antisocial or delinquent behavioral problems. Aggressive behavior during childhood, poor academic achievement, and school failure are other factors. 20 references