And in severe psychoses leading to the murder of your fellow human beings and of yourself there's usually a host of contributing factors, including genetic and develomental. Why shootings are specific to America, the rest of the world seems to think, is because firearms are readily available here. Indeed, while there may not be so many shootings in other developed countries, you would have to evaluate the statistical incidence of other violent behaviours to judge whether there is any "American specificity" beyond the "method of choice." -This is also addressing an earlier comment by Peter.I believe that it very important to address aggravating factors in society (violence in movies, etc.), but I do not think that they are the direct "cause" of extreme violence from psychologically unbalanced individuals. I also believe this is very important because it means that a lot of research still needs to be done on biological factors of mental disease, and that this will eventually present us with the hope of treatment for those affected.The debate on firearms availability musn't be avoided, either. If we reduced firearms availability and diminished representations of violence in our media, we would most likely decrease vilent events in everyday life; but would it prevent individuals with severe psychiatric disorders from harming themselves or others? I seriously doubt it.