This movie elicits confusion and despair by entering a desperate man's hallucinations, evoking his paranoia. It's painful, depressing, and powerfully written, directed, and acted.

An American soldier in Vietnam (Robbins) faced shocking battle experiences only hinted at, and has returned to civilian life as a psychological time-bomb. He earns a doctorate he doesn't use; after a first marriage ends and a young son dies in an accident, he works for the Postal Service, and lives with a woman he meets there (Pena). Terrible things happen: He's nearly run down in the subway, almost hit by a car, and his doctor and a friend die in a car explosion. Demons pursue him.

He thinks his war buddies and he are victims of an Army experiment. After a bloody battle, they all got dizzy; then he can't remember what happened. He was wounded and airlifted; flashbacks follow his emergency treatment. But then what? He and a group of fellow veterans talk to a lawyer about it, but the other vets and lawyer back out.(("Jacob's Ladder" rides on the raw edge of sanity, carrying us along. Is the "reality" all flashbacks? Or flashforwards? What was real, and what was only in the man's mind?

The point is a portrait of a mental state, as in Orson Welles' "The Trial" and Ken Russell's "Altered States." Lyne did well at determining what could be left out, replacing some of Rubin's material with the worse idea that paradise and the inferno are on Earth, and that we participate in one and/or the other.((The movie's main actors behave in a surrealistic, slice-of-life way (even in scenes later revealed as hallucinations), then coasts away into fearsome fantasy. Pena manages to create a believable, sympathetic woman with dimensions only the hero can guess at.

The story isn't the film's point, which is to evoke in the audience the feeling of a psychological state, to make us feel what the lead feels. This is a film about life and death; Jacob seems poised at the middle of a ladder reaching in two directions: up to heaven, like the ladder God put down for Jacob in Genesis, and down to hell, in drug-induced hallucinations. This movie isn't pleasant, but exhilarates; it lets us see filmmakers working at the edge of their abilities. Not every movie has to be fun.