Do you know the name of illness the Nakamura of this manga has?
Pls answer after reading the last chapter(57).

She has no illness... Those black shadows spewing flies are just a metaphor.

Seems like a mixture of schizophrenia and depression. There was definitely too much wrong with that girl for it to simply be a metaphor.

No, it's a metaphor.

Not everything has a standard name that can be used to pin it down and forget about it. Especially characteristics of people outside the standard collection of behavior patterns don't. Double-especially such people in literature. You are free to see her problem as some kind of internal darkness that you've never heard of before, or major depression, or oppositional personality disorder -- or maybe even, worse yet, something dark in your own self that you just learned through this manga to recognize!

But in another place and time they might call it something completely different, like devil possession, or evil nature, delinquency, incorrigibility, sinfulness, bad seed, etc.

In fact, people are endlessly complex, and literature just tries to show that.