This isn't the kind of book I'd usually read, but if it was a film I would pick it up in a heartbeat. The inside cover had me from mentioning that the narrator's sister has an early-onset case of Schizophrenia and then reading on further to realise that this is a horror novel -- well, I was definitely interested.
And for the most part I enjoyed this novel. I think my favourite bits were the chapters told from the point of view of a blogger who turns out to be the narrtor, blogging while keeping her identity secret because of all the analysis of exorcism, mental illness, feminism, and other things in popular culture that all weave together to tell the story of Marjorie and Merry's having to deal with their parents' marriage falling apart, Marjorie's onset of a certain mental illness, and the whole world being treated to the melt down of their family.
I recommend this book to fans of exorcism horror, the portrayal of Christian religion in media, those interested in mental illness, and those looking for a book that pretty much analyses itself as the story progresses.