In a survey of middle school and high school students on Chicago's South Side, nearly one out of four said they had seen someone killed. More than one third of the students -- 35 percent -- said they had personally witnessed a stabbing, and 39 percent said they had seen a shooting, the survey found. In about half of the cases, the student knew the victim as a friend, relative, classmate or neighbor.

Those findings, not yet published, are based on a recent screening of more than 1,000 Chicago students. They are cited in a new report calling for attention to the psychological effects of chronic violence on children in inner-city areas. The report is to be presented today at a conference on children at risk, held at Meharry Medical College in Nashville, Tenn.

The problem of "violence overload" tends to get sporadic and short-lived local attention after specific outbreaks of violence involving children, such as the school shootings in Winnetka, Ill., and Compton, Calif., note researchers Carl Bell and Esther Jenkins. But, they say, "children in inner-city areas where violence is chronic often do not receive such attention."

Bell is a psychiatrist at the University of Illinois School of Medicine in Chicago, and Jenkins is a psychologist at Chicago State University. Both are affiliated with the Community Mental Health Council of Chicago.

The consequences of violence extend far beyond the direct victim, Bell and Jenkins say, and can affect witnesses, particularly children, making them "more likely to engage in future violence and other antisocial acts."

Witnessing repeated acts of violence can affect children in many ways, their report says, depending on the age and personality of the child. Preschool children may grow passive and untalkative and become bedwetters. Adolescents may "engage in acting out and self-destructive behaviors such as substance abuse, delinquency, promiscuity, life-threatening re-enactments and other aggressive acts," Bell and Jenkins say.