Psycho (1960)

One of cinema's premier horror characters is Norman Bates (Anthony Perkins), the subject of Alfred Hitchcock's classic Psycho. He is a schizophrenic with two personalities: the mild-mannered Norman, who graciously caters to his guests at the Bates Motel, and Norman's homicidal deceased mother Norma. The four-time Oscar nominee is a chilling film, but it showcases the seamless transition between personalities that schizophrenia permits.