Suspense with Mental Issues

Dark, twisted, suspense with complex characters dripping with issues.
I loved her paranormal series and expected something other-ish to fill these pages. Yes, I do pick up books I know nothing about and start reading, it's fun to be surprised. Back to the point, I was reading about these troubled teens who had been brought together for this weekend therapy, in a remote location, with no windows and I expected ghosts, vampires, special powers ? They had no powers, no para-anything and not a touch of sexual tension, and I was glued to the pages. Why ? The story was interesting, there was something off about everything happening, the answer just out of focus. I also grew to adore the two main characters. Max was a jumbled mess, living bare footed on broken glass. Riley, was the girl who lived a horrendous night. She is filled with survivors remorse. Together this most unlikely duo become more than society accepts.
There is a lot of death, blood, murder in this story. It is graphic, and happens through most of the book. Suicide also comes up FYI. I am not sure I would call this YA reading.
I loved the book. It held me, made my adrenaline spike, my heart break and kept me guessing to the end. I hope she writes more stand alone reads like this.