Seems to me there are three components to the violence we are trying to stop:
1. Mental impairment (illness) of the individual
2. Lifetime of "violence de-sensitation"--violent video games, movies etc
3. Access to guns
We need to discuss all three components. For example, just talking about gun control is not the answer. In New Zealand, with very strict gun control, when someone goes off the deep end and starts stabbing or hatcheting people, the cops come on the scene and shoot the person. Sounds good until you think, gee, do we really want to have our cops shoot our mentally ill teenagers with "intermittent explosive disorder". You can say yes, until you think back on all the public outcry every time a cop shoots a teen.