Maybe, but, it's more likely related to additional mental problems. First realize that the thinking patterns of todays youth is so much different than that of 20 years ago. Their concept of murder is different than yours and mine are. Our beloved America has many problems today. Our children are mezmorised by anti everything that is not fast, easy, online, social. They are convinced that everything has to be faster, without consern for quality. My Son spends alot of spare time on his internet. Most young people do. The challenge is to win, win, win. at video games and other stuff. Not to learn and achieve as we were taught.
Our schools don't make then think. Friends are internet people that they have never met. Computers provide recreation but was initally conseived as a work and research tool.
It's not about teachers, they are told what they have to teach. It's not about guns or knifes cause they have been a part of good homes for 100's of years.
Our children are extremely f***ed up because we let our society got that way. Computers and wireless tech, marketers making them believe "you gotta have a cell phone" and fast internet to be a man or woman. I prefer touch and a warm fire..