Early Tuesday morning, hundreds of people braved the cold to be among the first to own the latest Call of Duty video game.
War games are increasingly popular because they immerse the player in the experience.
But Senior Health Correspondent Monica Robins has a word of caution, especially for parents.
Violent video games have been around for at least two decades, so there's been several studies done on how they affect our brains.
And just as the adrenalin amps up the player, the violence changes our brain.
The concern is that scientists don't know how long it lasts.
They create a different emotional experience and scientists think it desensitizes individuals to violent acts and may make them less compassionate.
The brains of violent video game players showed less activity in teh areas of emotion, attention and inhibition of impulses.
Similar brain changes are seen in people with destructive, sociopathic disorders.
It doesn't mean you turn out to be an aggressive hostile person but we do know it's changing brain chemistry and causing our bodies to be more aroused.
The part of the brain that can distinguish between reality and fantasy doesn't completelt develop until age 25.
These games are meant for mature players, not children.
They advise to keep your kids away from these games. It has that mature rating so don't buy this game for your children.
Another risk of any video game is addiction.
Video game rehab centers are popping up around the country because sometimes, gaming can take over someone's life, similar to gambling, drugs or alcohol.
If a game is interrupting work, social interaction or being used to escape from life, it may be time to talk to a psychological specialist.