I'm sure a number of us remember what happend to the wrestler Chris Benoit and the media made it look like he had a moment of "Roid Rage". Nightline ran a update on what might have happend to him and why he snapped. His father let Doctors look at his brain and discovered a large amount of damage. Most likely due to the repeated concussions over his career. It's a very interesting theory. I find that it's hard to rule out. I've personaly had 2 concussions and after the 2nd one I've never felt the same.
Chris Benoit's Dad: My Son Suffered From Severe Brain Damage - ABC News