May 25, 2010 (New Orleans) -- Young, healthy men who play a lot of violent video games over a long period of time show distinct changes in brain activity that correlate with aggressive behavior, preliminary research suggests.
A number of studies have linked frequent use of violent video games such as Grand Theft Auto and Manhunt to aggressive tendencies in kids. But other studies have found no such link.
There has been little research into whether the games have an impact on brain function.
The new study involved 14 young men, average age 25, who said they played violent video games an average of five hours a day for at least two years, and 14 young men of similar ages who didn't play violent video games.
The findings were presented at the annual meeting of the American Psychiatric Association.
Video Games and Aggression
Results showed the players of the violent games had substantially higher scores on the aggression questionnaire. And they showed increased activity in the brain's default mode network -- a series of connected areas that work hardest when most of the brain is at rest -- compared with the non-players.
High activity in the default mode network indicates reduced cognitive activity during resting periods, says researcher Gregor R. Szycik, PhD, of Hannover Medical School in Germany.
Statistical analysis showed the increased activity in the default mode network correlated with higher scores on the aggression questionnaire, he tells WebMD.
The work is very preliminary and does not show that violent video games lead to aggressive behavior, Szycik says. If there is a link, "we don't know which comes first, the aggression or the violent game playing."
"The work is a nice step in the right direction, using a novel approach to look at the impact of video games on human behavior," says Donald Hilty, MD, co-chair of the committee that chose which studies to highlight at the meeting. Hilty is a professor of psychiatry at the University of California, Davis.
"It suggests that when you stop a high-intensity activity, you might not be the same as usual. It's not like you'll go out and shoot someone, but your mental skills may not be quite as sharp, just like when you watch too much TV," Hilty tells WebMD.
Moderation is key, he says. "If you do anything too much, even exercise, you'll run into trouble."
This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.