THURSDAY, July 29 (HealthDay News) -- Even in so-called "good" neighborhoods, there's a significantly increased risk of violence if teens gather with nothing to do and no adult supervision, a new study suggests.

It included 842 young people who took part in a long-term study of Chicago neighborhoods. The participants were first interviewed when they were between the ages of 8 and 13 and again in series of follow-up sessions over an eight-year period.

Levels of violence differed according to the types of neighborhoods the participants lived in, but higher levels of violence tended to occur in neighborhoods that often had unsupervised groups of teens. This included "good" neighborhoods where residents trust and help each other and watch each other's children, the researchers found.

The study appears online July 26 in the journal Criminology.

"Even if you trust all your neighbors and all the teens are 'A' students, it is best to assume that groups of teens just hanging out can lead to problems, including violence," co-author Christopher Browning, an associate professor of sociology at Ohio State University, said in a school news release.

Previous research has shown that unstructured gatherings of teens can lead to general misbehavior, but this is the first study to suggest it may also increase the risk of violence, he noted.

The findings show the importance of adult supervision of youth activities, including after-school programs.

"Communities need both the shared willingness to control adolescent behavior in public space and the capacity to provide adolescents with options other than unsupervised 'hanging out,'" Browning said.

Noting that it was hard to gauge exactly how much supervision kids needed, Brown added, "Parents are better off assuming that more structure is better for their teens."

More information

The American Psychological Association outlines the warning signs of teen violence.