It’s no secret that spending too much time in front of the TV or computer is not the best thing for kids’ brains, but a new study finds that more than two hours per day may actually harm a child psychologically. The researchers found that too much screen time was linked to psychological problems like attention deficits and hyperactivity.

The researchers found that spending at least two hours in front of the TV was linked to a 61% increased risk of having psychological difficulties.

Over 1,000 children aged 10 to 11 were surveyed as to how much them they spent in front of the TV or computer. They also filled out a questionnaire called Strengths and Difficulties, which was designed to measure significant behavior issues like attention, hyperactivity, problems with conduct, and social skills. These behaviors were considered to makeup a measure called psychological difficulties, and this was correlated to how much screen time the kids engaged in every day.

The researchers found that spending at least two hours in front of the TV was linked to a 61% increased risk of having psychological difficulties, while spending two hours on the computer was associated with a 59% increase in psychological problems. These results held true even when the researchers controlled for factors like age, gender, and how much physical activity the kids got. (Boys did tend to spend more time at the computer than girls did, but this did not affect the main finding in the study.)

Finally, the more sedentary the children were, the more dramatic the risk of psychological problems: for the most sedentary kids, those who watched more than two hours of TV were at a 70% increased risk of having psychological problems, and for computer time, this risk jumped to 81% (compared to the most active children).

Page and her team say that the results are particularly striking since, according to previous research, many families believe that two hours of screen time is totally acceptable and part of a "balanced lifestyle". Current government recommendations for healthy amounts of screen time may need to be reevaluated, as more and more studies point to the ill effects of too much time in front of the tube.

The research was carried out at the University of Bristol and published in the October 11, 2010 issue of Pediatrics.