A new study concludes that children can become addicted to playing video games, with some skimping on homework, lying about how much they play and struggling, without success, when they try to cut back.

In what is described as the first nationally representative study in the United States on the subject, researcher Douglas Gentile of Iowa State University found that 8.5 percent of American youths ages 8 to 18 who play video games show multiple signs of behavioral addiction.

"For some kids, they play in such a way that it becomes out of balance. And they're damaging other areas of their lives, and it isn't just one area, it's many areas," said Gentile, a psychologist and assistant professor whose study was posted online today by the journal Psychological Science.

To get at gaming addiction, Gentile adapted diagnostic criteria for pathological gambling into a series of questions about video game use. The questions became part of a 2007 Harris Poll survey of 1,178 children and teens. Gamers were deemed "pathological" if they reported at least six of the 11 symptoms.

Symptoms included spending increasing amounts of time and money on video games to feel the same level of excitement; irritability or restlessness when play is scaled back; escaping problems through play; skipping chores or homework to spend more time at the controller; lying about the length of playing time; and stealing games or money to play more.

Four times as many boys as girls were considered "pathological gamers."

Gentile said he started his research with doubts about the possibility of addiction. "I thought this was parental histrionics -- that kids are playing a lot and parents don't understand the motivation, so they label it an addiction," he said. "It turns out that I was wrong."

What he found, he said, was that children considered pathological gamers did worse in school, had trouble paying attention in class and reported feeling "addicted." They were twice as likely to report attention-deficit disorder or attention-deficit hyperactivity disorder.

The study found that 88 percent of the nation's children ages 8 to 18 play video games. With 45 million children of that age in the country, the study would suggest that more than 3 million are addicted "or at least have problems of the magnitude" that call for help, Gentile said.

"It's not that the games are bad," said Gentile, who is also director of research at the nonprofit National Institute on Media and the Family. "It's not that the games are addictive. It's that some kids use them in a way that is out of balance and harms various other areas of their lives."

The study said that the findings leave many questions unresolved. The study could not say, for example, whether pathological game-playing caused poor school performance or whether "children who have trouble at school seek to play games to experience feelings of mastery."

Gentile also said the research did not indicate what the warning signs of addiction might be or how to best treat such a problem.