Introduction
After reading mills' text on school shootings and post-structuralism I started thinking about the reasons why a school kid would run amok. I began to link the subject matter with other thoughts of mine about related subjects. I also found some other nodes on E2 that seemed to tie in with the general problem, so of course they're hardlinked at the appropriate places.
Theory
Let's begin with the groundwork: All people are in need of identity. Especially in today's individualistic society, a person needs to be somehow distinct from everybody else. If somebody becomes indistiguishable from others, then that person ceases to be an individual. In a way he or she therefore ceases to exist. Being distinct is the key to your survival. Else you become an unperson.
TV
Look at a TV soap or something similar. Notice how all the characters are happy and without any real problems. Notice how perfect they are - much better, much wittier than you can ever be. And above all, much more interesting. Just watch enough TV and their fictional life will become more real than your own, because while everybody pays attention to them, nobody pays attention to you. You are uninteresting and therefore you do not amount to anything. You are irrelevant. This puts you in danger of effectively ceasing to exist. (1)
Saving yourself from Oblivion
Of course, you would like to continue to exist. So what can you do? You must become interesting enough to make people notice. And there's basically two ways to do that. Either you can look at the interesting people and try to imitate them, or you can try to distinguish yourself in some other way.
Role Models
Do you smoke? If so, why? Look at movies: there's that classic image of the cool guy smoking, in all its variations. Todays incarnation is the machine-gun-toting badass having a smoke in a corner after just mowing down a small army of Bad Guys. Or an older variant: the powerful, cigar-smoking mafioso. So you might subconsciously begin to imitate them, and start smoking. This has nothing to do with your being stupid or gullible - I've noticed it on myself. Though I am a rather vehement non-smoker, I have caught my right hand in a very revealing gesture several times now: My index and my middle finger, held together, stretched out. Just right to hold a cigarette. And I hardly ever watch TV.
Many people can stave off their fears by imitating people they think are more important than themselves. Cliques are also another way to get yourself acknowledged. If you adhere to the standards of a clique (clothing, language, who to beat up), its members will respect you, and you will belong. Cliques are basically groups of people constantly re-affirming each other's importance.
Reaching for the Top
That doesn't work for everybody, however. Social outcasts and those who are simply a bit too perceptive to get caught up in those trends have to find other ways. As I mentioned above, the other way to matter is by distinguishing yourself from the others in some interesting way. There are many ways to do this. Science, Sports, Good Works, Art, Writing (a good bet if you're reading this). Unfortunately, it isn't really sufficient to do these things. You have to do them reasonably well. What's the point of being an artist when people are indifferent to your work? What's the point of trying to help people when you're incapable of it? So this way of escaping from oblivion is barred to many. To be honest, it's barred to all those lacking the necessary talent, ambition or stubbornness.
Drugs and Violence
Having exhausted the harmless ways of dealing with this problem we now turn to the dangerous ones.
Drugs are a great way of getting over your feelings of worthlessness. Just get yourself high enough and you won't feel anything bad at all. Problem is that you can't stay on drugs all the time. You got to get money for them. Oh yes, and they might kill you eventually.
What's left for the social outcast without any hope of success and without ready access to drugs? Somehow he needs to make other people notice him, somehow he must show that he amounts to something, show that he can't just be ignored, traded for the people on TV. Somehow he has to become more interesting than soap operas. And the easiest way to do that is to appear on the evening news. Shoots a few people and he's on. Suddenly he matters more than soap operas, if only for a short time. What comes afterwards does not really matter. All that matters is his short moment of glory.
(1) If something does not affect the world in any way, does not interact with it, then it does not exist. An example: I posit the existence of a giant blue dog in your backyard, digging up bones. But when you look outside and notice neither blue dog, nor bones, nor holes, then you will conclude that the giant blue dog does not exist.