It's the haunting thought on everyone's minds since the horrific killings. Did Nick Reiner understand what he'd done when he allegedly murdered his parents Rob and Michele? What state of mind was he in?? We know he was acting erratically and making people uncomfortable at Conan O'Brien's Christmas party the night before. He'd struggled with addiction and mental health most of his life, experiencing drug-fueled rages, and was even diagnosed with schizophrenia.