Let's face it: high school is a hard time for any kid, no matter what social group the kid is in. There have been documented cases of the most popular kids in school committing suicide and sometimes the most unpopular kids are the happiest in their own group. The thing every kid has in common is the pressure exerted from friends, the media, parents, teachers, guidance counselors, the list can go on and on. So why do kids turn to violence? Is it because they are sociopaths or are they responding to external stimuli?

I believe only a tiny portion of teenage violence is because of sociopath behavior. True sociopaths are very rare and generally the behavior doesn't present until they are in the late teens/early twenties. 

The more likely reason is because of depression. Depression manifests in many different ways and sometimes it can manifest in anger and the anger can repress itself for a while. If a kid is being bullied at school or doesn't fit in or conform to social norms then it starts to take its toll on the person. 

Depressed people often have harmful thoughts, sometimes those thoughts are about hurting themselves (eating disorders, cutting, suicide) and sometimes the thoughts are about hurting others; particularly those people who the person in question might blame for feeling depressed. If a depressed person has a specific bully that never gives them a break then that person might take out his/her anger on that person. 

School violence is an awful epidemic that seems to be spreading but I believe that it can be slowed down. I believe with the donations of many to organizations or to the local high schools to fund psychiatric or guidance programs, these events might be prevented. If a depressed person is diagnosed as depressed and has help before he/she has time to take action on any plans to hurt his/herself or someone else, school violence could dramatically decrease.