Hello! I saw your question on ELatimer's message board and I just felt like saying something. Sorry for being so random.
As Erin said, you shouldn't restrict yourself to write something for a particular category. You write, then you categorise. You can change it later.
As for violence and psychoness, I'm telling you, half of the YA books I've read are like that. YA books aren't all teenage romances. There's heaps that are about psychotic murderers and mass slaughterers. So you really don't have to worry about it. Front and foremost, write what you want, not what others want because you won't feel compelled to continue writing and it won't be as good.