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, vampire mythology, lesbianism, motherhood, abortion and other subjects. The experimental style of its prologue and storytelling 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".