When you look for a why it boils down pretty neatly into two categories, for attention and infamy, as LanX has said, and mental issues, almost always exacerbated by medication; many anti-depressants and anti-psychotics have the opposite effect on some people, especially teens. Teen suicide in the US is up 70% in 10 years, on the same topic. No one is interested in the real causes though, only the medium.