This is one of the very few films that I came out of the theater crawling *under* the carpet... And I still find it disturbing - and at the same time or perhaps exactly because enlightening. Many of Bergman's films of that time dealt with the inherent self-destructiveness of the "human condition"; but most of them also had a plot element that involved an external destructive force: war (The Seventh Seal, Shame), the proximity of death (Wild Strawberries) and so on. Even Hour of the Wolf, the one that comes closest to Passion, has the "wolves" - the coterie that seduces Max von Sidow's character into reliving, facing, and ultimately succumbing to, his inner demons (by the way, make sure that your version of Hour of the Wolf includes the posface, "look, this is a movie, and we just wrapped it up, it's not real, you see, these people are just characters in a movie played by 'normal' people - but the demons will stay with you, cause they're not really ours, they're your own").
Not so Passion. Here, there is no outward force pushing these people - these "normal", whatever their personal demons, people - towards inescapable destruction. There is the wanton, unresolved slaughter of animals; but this doesn't touch the characters, no more than the everyday "slaughter of the lambs" that surrounds much of our lives does us except to at most evoke a vague disquiet, let alone drive them. They're doomed; always were. Nothing can save them. Not love, or the forlorn illusion of, not a bourgeois life surrounded by creature comforts, not even outburts of personal violence. There is simply no redemption.
For the "passion" is not "a" passion, but *the* passion, the passion that drives us all, and indeed all life: the endless collision and collusion between Life and Death, that sets down the boundaries within which we, like Von Sydow's character at the film's closing, must forever pace back and forth.