WASHINGTON - Children and adolescents who watch a lot of television are more likely to manifest antisocial and criminal behavior when they become adults, according to a new study published online Monday in the US journal Pediatrics.

The study followed a group of around 1,000 children born in the New Zealand city of Dunedin in 1972-73. Every two years between the ages of five and 15, they were asked how much television they watched. Those who watched more television were more likely to have a criminal conviction and were also more likely to have antisocial personality traits in adulthood.

Researchers from University of Otago in New Zealand found that the risk of having a criminal conviction by early adulthood increased by about 30 percent with every hour that children spent watching TV on an average weeknight. They also found that watching more television in childhood was associated, in adulthood, with aggressive personality traits, an increased tendency to experience negative emotions, and an increased risk of antisocial personality disorder; a psychiatric disorder characterized by persistent patterns of aggressive and antisocial behavior. And the relationship between TV viewing and antisocial behavior was not explained by socio-economic status, aggressive or antisocial behavior in early childhood, or parenting factors.

The researchers said that it is not that children who were already antisocial watched more television. "Rather, children who watched a lot of television were likely to go on to manifest antisocial behavior and personality traits."

The American Academy of Pediatrics recommends that children should watch no more than one to two hours of quality television programming each day. The researchers say their findings support the idea that parents should try to limit their children's television use.