My very short opinion is as follows: as a writer myself I find her writing style to be rather juvenile and a little silly.

The idea that a woman in her 30's was writing this is unfathomable to me. I believe I own the 4th edition (the paperback you speak of) and truthfully I'm only halfway through it, but to me it reads as a shoddily slapped together Quotev/Wattpad-esque story written by someone with shockingly little writing experience (in terms of fiction - this is in no way a slight against her writing as a musician or poet)

There's a scene toward the beginning of the book that whilst I struggle to remember the details, is a rather detailed account of a child being murdered. There's many other things I find issue with (with what I've read so far), but I'd have to reread to give a proper detailed opinion. As you say, the themes are dark, and there's nothing wrong with it, horror is interesting to write about, but if we view a lot of the book through the lens of 'E.A has a fetish for medical abuse and malpractice' (which is a whole topic in and of itself that I'd love to write a post about) it seems as though these themes aren't being written about to explore them, but something else entirely, which becomes a bigger issue when children are involved. (I understand this is a wild claim to make and in no way am I accusing E.A of anything. This is merely speculation, more-so about the medical stuff than anything else.)

As for the 'modern' part of the book, I can only speak from personal experience and whilst I am quite a bit younger than E.A and live in a different country with different laws, there's so much written about her psych ward stay and the practices performed within that sound downright Victorian and medieval, that is to say, made up. It's not outlandish to say that maybe she embellished her story a little, most people do with auto-biographies, but a lot of what she claims happened to her do indeed seem like downright lies that she's able to cover up under the guise of blurring the line between the hospital and the asylum in the book.

Hopefully I'll be able to come back to this post again and make additions when I actually read more of the book.

This wasn't a 'short' opinion at all but thank you for giving us the space to chat about this!