Okay so uhh I'm gonna change Amelio a bit.
I think it's stupid that he's burden with everyone's problems when nobody actually complains to him (in his family)
So what I'm gonna do is that the reason he does everything is because he does it for attention. I've noticed nobody actually pays attention to him, yes including Jerry and Max when they're enraptured by each other.
So he does the cutting, his depression (starting out fake), his stupid ideas, everything he did was out of wanting attention from people and it became so bad that he actually got depression and it became a habit to start cutting everyday.
Instead of hurting others, he started hurting himself.
Obviously it stopped when Shadow started paying him attention and they got together, but y'know just changing it up