Ingmar Bergman's films always had, or at least, most of them had, a very dark and almost horror-ish tone to them, particularly films such as "Persona" and "The Seventh Seal", both which I consider among the finest films ever made. It was no surprise that his two 'official' horror films - this one and the slightly superior "Hour of the Wolf", come across as being not only of the genre's finest, but also one of the scariest of all time. Liv Ullman gives a breathtaking performance of a psychiatrist who turns out to be just as crazy as the people she takes care of. We follow her as she is lost in the hellish labyrinth of her subconscious, and harassed by horrible demons she created herself. Meanwhile, on the outside world, her 'darker side' takes over, and her friend and co-worker, played by the great Erland Josephson, tries to save her. Ullman's gradual descent into insanity is jaw-dropping, and here she gives her most twisted, hysterical performances for the likes of Isabelle Adjani in "Possession" and Catherine Denueve in "Repulsion". For the acting and Bergman's superb direction alone the film manages to convey a sense of dread and fear unlike anything Hollywood had done to this point, and indeed, the film does make the majority of American horror films made at that time look stupid in comparison. Overall, 10/10. A masterpiece.
