He's a tranvestite!
Dr. Fred Richmond
Ah, not exactly. A man who dresses in women's clothing in order to achieve a sexual change, or satisfaction, is a transvestite. But in Norman's case, he was simply doing everything possible to keep alive the illusion of his mother being alive. And when reality came too close, when danger or desire threatened that illusion - he dressed up, even to a cheap wig he bought. He'd walk about the house, sit in her chair, speak in her voice. He tried to be his mother! And, uh... now he is.