The Grinch who stole my Sanity

16 year old Luminescence Evergreen was found on Christmas day in a warehouse filled to the brim with Christmas decorations with all kinds of weird markings all over her body. She was wearing nothing but a Christmas tree skirt and and attacked the officers that arrived on site when she came into view of them. She bit one of them and had to be restrained and sedated.
She had last been seen 3 weeks ago at a party out with her friends. So what happened during those 3 weeks that had literally made her go totally mad?