MONDAY, July 5 (HealthDay News) -- Too much time spent watching television and playing video games can double the risk of attention problems in children and young adults, new research finds.

The study is the latest of many to point out the ill effects of excessive screen time, whether at the computer or the television.

Researcher Edward Swing, a graduate student at Iowa State University, compared participants who watched TV or played video games less than two hours a day -- the recommendation from the American Academy of Pediatrics for children aged 2 and older -- to those who watched more.

"Those who exceeded the AAP recommendation were about 1.6 times to 2.2 times more likely to have greater than average attention problems," he said.

The middle schoolers he studied were a little less likely than the college students to have attention problems with excess TV and video game participation.

The study is published in the July issue of Pediatrics.

Swing and his colleagues looked at two age groups. They assessed more than 1,300 children in the third, fourth and fifth grades over a 13-month time period. They also looked at 210 college students for a one-time evaluation.

"The children were reporting their TV and video game use and the parents were also reporting TV and video game use," Swing said. "The teachers were reporting attention problems," he said of the middle school students.

Teachers reported if children had problems staying on task, paying attention, if they interrupted other children's work, or showed problems in other areas that reflected trouble with attention.

College students did self-reports on their attention problems.

Middle school students spent an average of 4.26 hours a day watching TV or playing video games, the team found, while older students spent 4.82 hours daily.

Previous studies have also linked screen time with attention problems.

"There may well be a relation between television viewing and attention problems," said Dr. David Elkind, professor emeritus of child development at Tufts University and author of The Power of Play.

But he had some caveats about the new study. "Teacher ratings of attention deficit have been shown in other studies not to be consistent over time," Elkind noted.

In response, Swing said they did have more than one teacher rating the children and that the ratings tended to be in agreement.

"This is an important finding," according to Dr. Dimitri Christakis, the George Adkins Professor of Pediatrics at the University of Washington in Seattle. He, too, has researched the topic.

"ADHD [attention-deficit hyperactivity disorder] is 10 times more common today than it was 20 years ago," he said. "Although it is clear that ADHD has a genetic basis, given that our genes have not changed appreciably in that timeframe, it is likely that there are environmental factors that are contributing to this rise." He and other experts suspect excessive media as a contributor.

"These media aren't going away," Christakis said. "We do have to find ways to manage them appropriately."

"Content matters," he said. His own research found that the faster-paced shows increased the risk of attention problems. Why? "You prime the mind to accept that pace. Real life doesn't happen fast enough to keep your attention."

Elkind also pointed out that, "it makes a difference what kind of show or computer games the child is playing." Shooting games, for instance, are different than problem-solving computer games.

The study should have accounted for these variables, he said.

Swing agreed, and added he hopes to study that next. Meanwhile, he said, the recommendation of less than two hours a day of screen time seems prudent.

More information

To learn more about television viewing guidelines, visit the American Academy of Pediatrics.