[gavanwoolery]

In some cases it is desperation, but often (I suspect) it is the dangerous mixture of being bullied and having psychological or socially-incurred disorders. Of course, it is never these things that are blamed, it is gun laws, or video games, or movies, or music...

[aaronem]

I'd argue that such disorders, where present, contribute in that they make it more likely that any given bullied kid will reach that rare pitch of desperation which finds its expression in a shooting spree.