I've lived in the US for 10 years, and I follow plenty of world news. It is clear that Columbine-like shootings are (mostly) an American phenomenon. [1]
So what is it so special about the US that makes this a recurring problem?
Is it poor parenting, without much communication? Is it societal pressure, i.e. Mr Popular vs Mr Loser? Is it easy access to guns? Is it the disproportionate amount of media attention that these cases give to depressed folks with low self-esteem? Is it all of the above? None?
I imagine severe depression happens everywhere, but there's got to be something in the US that turns depression into mass murder. I wish someone would analyze the problem from outside the box, not inside.
[1] Before someone jumps the gun about international news, note that terror and drug/gang crimes are very different. They have clear, consistent motives. Columbine-like stuff is puzzling- their motives seem to be all over the place, hence why to this date experts are still trying to figure them out.