http://www.guardian.co.uk/theobserver/2010/mar/21/tom-bissell-video-game-cocaine-addiction
An interesting read. He's talking more about the effects of his cocaine habit than the game but its just so sad that when a lot of people (on both sides of the argument) see it, they're going jump to the conclusion that he's blaming the game

Clearly GTA4 made him do insurmountable amounts of cocaine.

Clearly cocaine made him play insurmountable amounts of GTA4 ;-)

Clearly cocaine is addictive and should be made illega... oh...

Clearly GTA is addictive and should be made illega... oh... wait.
Maybe I should play GTA 4 but with some pharmaceuticals instead.

I did cocaine, once. I still have to play GTA IV, though :-P