Anja writes of the other version of death by computer game: when the games make people kill others, not themselves.
The problem is that games more often mimic life, than life mimic games. Shootings in schools is not new - it's not even exclusively an American phenomenon, something we Europeans can feel superior about and claim has to do with the deterioration of European culture by dirty US influence.
We have made schools extremely important institutions in the socialisation of children and youths, and they take over more and more of the responsibilities of families. When we know that statistically most violent crimes are kept in the family, we should not be surprised that the agression also turns against the extended family: the school.