There might be trouble brewing behind the glassy eyes of kids who spend too much time and energy on video games, according to a controversial new study.
In the 2-year study of more than 3000 school children in Singapore, researchers found nearly one in ten were video game "addicts," and most were stuck with the problem.
While these kids were more likely to have behavioral problems to begin with, excessive gaming appeared to cause additional mental woes.
"When children became addicted, their depression, anxiety, and social phobias got worse, and their grades dropped," said Douglas A Gentile, who runs the Media Research Lab at Iowa State University in Ames and worked on the study.
"When they stopped being addicted, their depression, anxiety, and social phobias got better."
He said neither parents nor healthcare providers are paying enough attention to video games' effect on mental health.
"We tend to approach it as 'just' entertainment, or just a game, and forget that entertainment still affects us," he told Reuters Health in an e-mail. "In fact, if it doesn't affect us, we call it 'boring!'"
But an independent expert said the study had important flaws.
"My own research has shown that excessive video game play is not necessarily addictive play and that many video gamers can play for long periods without there being any negative detrimental effects," said Mark Griffiths, director of the International Gaming Research Unit at Nottingham Trent University in the UK.
"If nine percent of children were genuinely addicted to video games there would be video game addiction clinics in every major city!" he said in an e-mail, adding that the concept is not currently an accepted diagnosis among psychiatrists and psychologists.
Part of the problem, Griffiths argued, is that the new work may be measuring preoccupation instead of addiction.
In the study, teachers handed out questionnaires to students in the third, fourth, seventh and eighth grades, including questions about their gaming habits, social skills, school performance and depression.
The kids also answered ten questions to find out if they were addicted to gaming - so-called "pathological" gamers. If they answered half in the positive, they got the label.
The questions included things like having neglected household chores to spend more time on video games, doing poorly on a school assignment or test as a result, or playing video games to escape from problems or bad feelings.
On average, the kids said they played about 20 hours a week. Between 9 and 12 percent of boys qualified as addicted in this study, compared to 3 to 5 percent of girls.
Of those children who started out as addicts, more than eight in 10 remained so during the study. "It's not simply a short-term problem for most children," Gentile said.
While the researchers didn't put a number on how many youngsters had mental problems, they did find that those who played longer hours, were more impulsive or had poorer social skills were at higher risk of getting "addicted" over the 2-year period.
Those who did become addicted reported increasing symptoms of depression, anxiety and social phobia.
Gentile said it appeared that unhealthy gaming habits were fueling the kids' mental problems, which then in turn might cause them to up their screen time and so forth. But he acknowledged his research didn't prove that point.
In an earlier US study, he found that children who watched a lot of TV or played a lot of video games had slightly more problems concentrating on school work. However, that study couldn't prove that screen time was at the root of the narrowing attention span, either.
The American Academy of Pediatrics, which published the new study in its journal Pediatrics, recommends limiting children's time in front of computers or TVs to 2 hours daily.
"One thing we have to bear in mind is that children playing video games for 2 to 3 hours a day is normal. It's displaced activities like watching TV," Griffiths said.
Still, he said a small minority of kids probably do suffer from true video game addiction, just as some people are pathological gamblers.
In general, Griffith advises that parents try to give their kids educational games instead of violent ones, encourage playing in groups, and follow the directions from the manufacturers, such as sitting at least two feet from the screen and not playing when feeling tired.
"I have three kids, all of who are the archetypal 'screenagers' who spend a lot of time a day interacting with technology" said Griffiths. "Basically, even when playing a couple of hours most days it is not impinging negatively on their lives."