My response to parents who say videogames make their children violent or depressed has always been, "Try parenting." It's a lot easier to point the finger of blame at something (ANYTHING) else than it is to accept little Timmy is making all the wrong decisions because of something you did wrong, or didn't do at all, as a parent. If you're worried about video games, maybe you should be taking a bit more interest in your child's development and emotional and mental wellbeing than letting Tommy Vercetti babysit them to keep them quiet. When I was a kid, I played games a lot, but I had a lot of friends, and my mother, though not perfect, always made a point of setting aside one of her days off as Mother-Daughter time... considering she was a single parent and worked MASSIVE amounts during the week, that meant a lot.
I mean, really? Really? If parents are so concerned about violence and aggression, why aren't they talking to their kids about it? Shielding a child from something is nice, but not as nice as sitting down and talking to them about real life versus fantasy, and what's important about being a caring, genuine human being. The only one responsible for how your child turns out is you.
All I know is a childhood of playing everything from Mario to Resident Evil to Grand Theft Auto has done little more to me than making me more willing to resort to dirty tricks in tickle fights with my husband.