Characterized by elements of psychological horror, Persona has been the subject of much critical analysis, interpretation, and debate. The film's exploration of duality, insanity, and personal identity has been interpreted as reflecting the Jungian theory of persona and dealing with issues related to filmmaking, vampirism, homosexuality, motherhood, abortion, and other subjects. The experimental style of its prologue, storytelling, and end has also been noted. The enigmatic film has been called the Mount Everest of cinematic analysis; according to film historian Peter Cowie, "Everything one says about Persona may be contradicted; the opposite will also be true"