Jacob's Ladder is a 1990 psychological horror film directed by Adrian Lyne, based on a screenplay by Bruce Joel Rubin. It starred Tim Robbins, Elizabeth Pena, Danny Aiello, and Jason Alexander. Actor Macaulay Culkin appears briefly in an uncredited performance that predates his wider fame. The film examines the disturbing experiences of Vietnam War veteran Jacob Singer, who begins to have hallucinations as he and other members of his former unit are pursued by unknown killers.

The film opens on October 6, 1971. Jacob Singer (Tim Robbins) is an Air Cavalry soldier in the Mekong Delta, Vietnam. Helicopters pass overhead, carrying supplies for what appears to be preparation for a big Viet Cong offensive. Without any warning, Jacob's unit comes under fire. The soldiers try to take cover, but begin to exhibit strange behavior for no apparent reason. Jacob tries to escape the unexplained insanity, only to be bayonetted by an unseen enemy.

The film shifts between Vietnam, to Jacob's memories (and delusions) of his son Gabe (Macaulay Culkin, uncredited) and former wife Sarah (Patricia Kalember), to his present (this timeframe is set in 1977) relationship with a woman named Jezebel (Elizabeth Peña) in New York City. During this time, Jacob faces several threats to his life and has severe hallucinatory experiences. It is revealed that his son Gabe was hit by a car and killed before Jacob went to Vietnam.

Jacob's friend and chiropractor Louis (Danny Aiello) states the main thematic point of the film: in effect, hell is really purgatory, and those who are ready to let go of their lives do not find the experience 'hellish'.

As the hallucinations become increasingly bizarre, Jacob learns about chemical experiments performed on U.S. soldiers in Vietnam. He is approached by a man named Michael Newman (Matt Craven), who claims to have been a chemist working with the Army's chemical warfare division in Saigon. He worked on creating a drug that increased aggression in soldiers. Tests of the drug (code-named "the ladder" in reference to the effect) were first given to monkeys and then to a group of enemy POWs, with gruesome results. Later the ladder was given to Jacob's unit, through the platoons' C-rations. However, instead of targeting the enemy, the men in Jacob's unit attacked each other indiscriminately.

We finally learn that Jacob never made it out of Vietnam; the entire series of experiences turns out to have been a dying hallucination. Jacob's experiences appear to have been a form of purgation in which he releases himself from his earthly attachments, finally joining his dead son Gabe to ascend a staircase toward a bright light.

At the end of the film, a message states that the U.S. Army allegedly experimented with an hallucinogenic drug called BZ, but the Pentagon denies it.

"The Ladder":
Jacob is told that the horrific events he experienced on his final day in Vietnam were the product of an experimental drug called "The Ladder", which was used on troops without their knowledge. This is an ambiguous element in the film, particularly since Jacob is given the information by a character in his own imagination. He is told that the drug was named for its ability to cause "a fast trip straight down the ladder, right to the primal fear, right to the base anger", although the name "The Ladder" also has a metaphorical and religious significance beyond this, which is relevant to Jacob's predicament: it is notable that he ends his hallucination on a staircase. At the end of the film, a message is displayed mentioning the testing of a drug named BZ, NATO code for a potedeliriant and hallucinogen known as 3-quinuclidinyl benzilate that was rumored to have been administered to Vietnam troops by the government in a secret attempt to increase their fighting power. The effects of BZ, however, are different from the effects of the drug depicted in the film.

Effects:
Director Adrian Lyne uses a technique, possibly the first of its kind, in which an actor is recorded waving his head around in blurred and horrific fast motion. Filmmakers have since achieved the effect by digitally removing frames from footage shot at a normal rate.

The horror videogame franchise Silent Hill borrows this technique in the second and third sequel of the game, although it is not seen in the Silent Hill movie. Other films to use the "fast-head" motion include Stir of Echoes, Austin Powers: International Man of Mystery, The Ring, Oldboy (2003), Trauma (2004), 1999's House on Haunted Hill, Dead Life, Lost Highway, The Amityville Horror (2005) and the Saw series. The music video for the Linkin Park song Papercut was inspired by this film.

The effect also appears in an episode of the television series Supernatural and in the X-Files Episode "Requiem", where it was applied to anyone entering an alien time-distortion field in the Oregon woods. The music video for "Stupify" by Disturbed, "Payback" by Flaw, Marilyn Manson's cover of Personal Jesus and Sober by Tool also use the technique. The Shalebridge Cradle level of the videogame Thief: Deadly Shadows has creatures that display this effect.

The movie's events are a dying hallucination related by an unreliable narrator. Director Robert Enrico had utilized a similar structure for his 1962 film short An Occurrence at Owl Creek Bridge, based on Ambrose Bierce's 1886 short story, and which appeared on American television as a 1964 episode of the fantasy-anthology series The Twilight Zone.

The film is also viewed by many, including the screenwriter, as a modern interpretation of the Tibetan Book of the Dead.