This was a really good thriller novel. An interesting premise, and it was very well executed.
Purified didn't have a slow start, it was gripping right from the beginning. There were a lot of possibilities, so I can't say that the novel was predictable. The whole time that I was reading this, a lot of speculations popped up in my head. A good novel does that. The book itself was written well, the timing of everything was perfect. The book never got boring for me, a lot of suspense every chapter. I did like the psychological-thriller genre novels I've read in the past, and I'm pretty sure I can consider this as one.
My only problem with the novel would be the flat characters. A lot of them were really forgettable, notably Warren, Steve, and Adam. Mason and Stace were the only ones interesting for me, and Dr Harlow of course, despite the problem stated though, I believe this deserves 4 stars. Not really sure if it's a standalone, hopefully not though. I really want more of this, a prequel or sequel would be nice.