New study findings provide scientific proof for what some have already deduced: teens exposed to violence are more likely than their peers to become involved in violence in the future.

Specifically, the study found that adolescents who witness gun violence or are the victim of gun violence are twice as likely as their peers to commit serious violence during the following two years after their exposure.

"The primary implication of these findings is that violence can be transmitted from person to person by means of exposure in the community," study author Jeffrey B. Bingenheimer, a doctoral candidate at the University of Michigan's School of Public Health stated.

"This makes the 'epidemic of violence' metaphor seem particularly apt, and is consistent with sociological theories of violent crime as a contagious social process," he added.

If, as this finding and other research suggests, "violence begets violence," the implications of increasing rates of violent crime along and adolescent exposure to violence, are troubling, the report states.

Bingenheimer and his team arrived at their finding from information collected over a five-year period from hundreds of adolescents involved in the long-term Project on Human Development in Chicago Neighborhoods.

At a first interview, 1,517 youths who were about 12 to 15 years old and their caregivers provided comprehensive information about themselves, including their family history, peer influences, vocabulary and reading skills, behavior and exposure to violence

At the second interview, the adolescents were asked if they had been shot, shot at or observed such gun violence during the previous year.

At the last interview, they were asked whether they had shot someone, used a weapon to attack someone, or otherwise perpetrated violence during the previous year.

Twenty-three percent of the adolescents reported that they had been shot at or otherwise exposed to gun violence and 12 percent admitted to being a perpetrator of serious violence, Bingenheimer and his team report in this week's issue of Science.

Their analysis indicates that adolescents who witnessed or experienced gun violence were twice as likely as those who had not been exposed to such violence to commit serious violence over the next two years.

The researchers note that they took into consideration the study participant's exposure to violence before the study began, their peer influences, behavioral patterns, neighborhood characteristics and over 100 other factors that could have affected the results.

"Our findings provide what we believe to be the strongest evidence available of a cause and effect relationship between exposure to community violence and violent behavior, but they do not constitute absolute proof of such a relationship," Bingenheimer stated.

Overall, teens who reported witnessing or being a victim of violence were more likely than the unexposed group to say they had used alcohol and drugs, had engaged in general delinquency and property crimes, had been physically abused, and had family members with criminal records. They also had lower vocabulary and reading scores and tended to live in more disadvantaged neighborhoods with higher levels of physical and social disorder. Such factors have previously been shown to predict violent behavior, Bingenheimer and his team note.

SOURCE: Science, May 27, 2005.