My opinion(s)..........
We have no evidence that Alyssa was into ICP music or was a Jugalette. I think that's irrelevent, but it was a very lively and informative discussion!
I don't think Alyssa was on a 3 day drug binge. She may or may not have been using illicit drugs at the time of the murder, or before, or after, or may have gone off her Prozac. IMO, it's not likely any illicit drugs "caused" her to dig graves on Friday and murder a child the following Wednesday. The Prozac affect, or lack thereof, may have played a part, not qualified to say.
Her hair, clothing, makeup, music choices are not inconsistent with those of her peer group. I know several of her friends and they are good kids. They use some foul language (not outrageous or extremely excessive, but some), some of them push the sexual boundaries a bit much for their age group (IMO), and they spend way too much time on the internet either playing online games (like WOW, boys only) or angsting on MS, FB, etc, over boyfriends and such. But they also participate in fund raisers for worthy charities, spend a lot of time practicing music (the ones I know play/sing in a band), read a lot (Twilight, etc), and get decent or better grades. They don't get in much trouble at school, never serious trouble, have involved parents, don't use drugs (that I know of), and are all currently focused on getting drivers licenses. Good, normal 15 year old kids who happen to have longish hair in their faces, wear too much eye liner, and mostly black clothing.
I had excellent parents, myself, but when I went to JCHS, I used drugs. At that time, nearly everyone did. If you didn't, you were ostracized. I also used alcohol. The 70's in JC were 100% drugs, sex, rock n'roll. It didn't matter how great your parents were, they had no affect. Kids do what their peers expect of them.