Both her parents were messed up. Her father killed and experimented and turned people into dolls. Her mother tried turning her into her father by reading her creepy stories, putting animals in her room so she'd kill them and put his chainsaw where Aya could reach it. You can read the mom's diary and find entries supporting this too. Aya never stood a chance. Though I still hate the true ending, as weird as it seems I like the doll ending.
I'm going to pretend she did open the clinic to help people (using her father's research book for good) as a form of redemption and had an awkward crush on Jean which is why she kept going on about her beautiful eyes. There fixed!