MONTREAL - Young teens will use violence in video games to "manage their feelings," say authors of a book about the impact of video games.

In their recently released "Grand Theft Childhood: The Surprising Truth About Violent Video Games," Lawrence Kutner and Cheryl Olson tell parents not to panic about video game violence.

Aside from playing for fun, kids play video games for creative reasons and to relieve stress, Olson said Tuesday.

"Also many children were using games to manage their feelings, and this seemed to be especially true for kids who played violent games like `Grand Theft Auto,"' said Olson.

Olson and Kutner, of Boston's Massachusetts General Hospital, were speakers at the Montreal International Game Summit, which showcases Quebec's gaming industry.

They surveyed about 1,250 people aged 12 to 14 in the United States over two years, asking them such questions as what video games they played, when they played and what they thought about violence in the games.

Many of the games that were played were violent and were rated "mature" for ages 17 and up.

"We have found that kids (who) were playing proportionately more `M' (mature rated) games and for more days a week are at a statistically higher risk of getting into fights and bullying other kids," Olson said.

That doesn't mean the video games caused the fights and bullying, but if the child is playing a lot and is isolating himself, parents should get involved, she said.

Violent games were sometimes used by boys when they were upset.

Boys would say if they had a bad day, got into a fight, or were yelled at by their teacher, they would go home and play "Grand Theft Auto" and "blow up someone who looks like the guy I feel mad at, and after I feel better and calmer," Olson said.

"It's possible if that were taken to an extreme, it could be a bad thing. I am guessing for an otherwise healthy kid, it's a healthy release for them," she said.

The "Grand Theft Auto" series has a mixture of action, driving and missions and focuses on different characters who try to rise through the criminal underworld through violent means.

Kutner and Olson are co-directors of the hospital's mental health and media centre. Their US$1.5-million study was funded by the U.S. Department of Justice to study the effects of video games on young teens.

The book has been largely praised by the gaming industry and video game fans for cutting through myths about violence and games but has had some detractors, including a psychiatrist who said the pair didn't take video gaming addiction seriously enough.

The students in the study said they were more concerned about "cursing" and "kissing" that their younger siblings could be exposed to while playing video games, Kutner said. Boys mentioned that there was kissing in "The Sims" game, which focuses on the lives of virtual people, he said.

"They kiss. If you think about it, if you're a 13-year-old boy, what's scary in the real world to you? That's it," Kutner said of kissing.

Olson said kids they surveyed understood the difference between violence in video games and the real world.

"They said one of the things they liked about it was the `un-reality.' They liked that they could try out being a thug or a gangster and do over-the-top things and then turn the games off."