People who spend a long time playing video games could be at greater risk of developing mental disorders such as Alzheimer's, new research suggests.
Scientists conducted a study of people who spent up to six hours a week playing action games, a genre which includes Call of Duty or Grand Theft Auto, and found they were more likely to rely on an area of the brain called the caudate-nucleus than non-gamers.
Using the caudate-nucleus to navigate is associated with reduced grey matter in the brain's spatial memory system, the hippocampus, which in turn has been linked with the "onset of many neurological and psychiatric disorders", the scientists said.
Dr Gregory West of the University of Montreal said: "For more than a decade now, research has demonstrated that action video game players display more efficient visual attention abilities, and our current study has once again confirmed this notion.
"However, we also found that gamers rely on the caudate-nucleus to a greater degree than non-gamers. Past research has shown that people who rely on caudate nucleus-dependent strategies have lower grey matter and functional brain activity in the hippocampus.
"This means that people who spend a lot of time playing video games may have reduced hippocampal integrity, which is associated with an increased risk of neurological disorders such as Alzheimer's disease."
In the study, published in the Proceedings of the Royal Society B journal, a total of 26 gamers and 33 non-gamers were tested on a virtual maze, with 80% of gamers using the caudate-nucleus compared to 43% of non-gamers, who relied on the hippocampus.
Researchers estimated gamers spent a total of three billion hours a week playing, with the average young person spending around 10,000 hours gaming by the age of 21.