Marianna Neal’s review published on Letterboxd:
Well, that's a bummer... I actually had some hopes for this one, but the movie is all kinds of "off", from casting to structure to dialogue. Chloë Grace Moretz does her best, and it's a very convincing performance, but it's just not enough to carry the rest of this. Also, I'm sorry to say, but she just comes off way too young for the role, along with Thomas Mann. This isn't a criticism of her actual work—once again, her performance was convincing, but based on the actual story behind this they should have cast someone a bit older.
Please, do yourself a favor, and read the actual memoir (also titled Brain on Fire) this is adapted from instead. The book is FANTASTIC, illuminating, and much more in-depth!