The following list supplements my ratings of
The 10 Scariest Movies of All Time. The reason for a sequel is simple. In my opinion, too many critics conflate "scary" and "disturbing" when compiling these lists. They're not the same. A
scary film is one that makes you afraid to be alone in the dark. A
disturbing film is one that makes you feel helpless, sick, angry, and ashamed of your own humanity. A film can obviously be both (notice
The Exorcist claims the top slot on both lists). As before I'm sticking with good films worth seeing. The critics don't necessarily agree with me; four of them are rotten tomatoes. On my other list only one was rotten, and it may be that disturbing films have to work extra hard at impressing elitists who have delicate sensibilities.
It's worth noting that most of the films on my scariest list come from an earlier period (between 1973-1981), while most on this list come from the recent decade. This is surely a general indicator of how horror films have evolved. It's getting harder to find truly scary and frightening films, but much easier to comes across disturbing and repulsive ones. Neither is necessarily superior to the other, though I do bemoan the rarity of the former these days.

(1)
The Exorcist. 1973. Critical approval:
85%. Disturb level: 99/100. When you get down to it,
The Exorcist is about a little girl being obscenely tortured. The demon thrashes her body into hideous contortions, scars her face, stabs her vagina with a crucifix, buries her mother's face in her bleeding crotch, vomits quarts of green puke across the bedroom, and barks the foulest vulgarities known to humanity. People threw up themselves and ran screaming from the theaters when it first aired in '73, and I doubt any film has had the same harrowing effect on so many viewers since. As Father Merrin explains to a troubled Karras -- who can't understand the point of such vile torment being inflicted on an innocent twelve-year old in the grand scheme of things -- "the point is to see ourselves as animal and ugly", which pretty much sums up the nature of disturbing films. It doesn't get more repulsive than this.

(2)
Martyrs. 2009. Critical approval:
52%. Disturb level: 96/100. The latest in a series of hard-core French horror films. A woman takes ruthless vengeance on people who tortured her when she was a child, and then kills herself in despair while her best friend gets abducted by the same atheist cult. It's her turn to be tortured as the cult prepares for her "transfiguration", the most perverse eschatological experiment conceivable -- a visit to the great beyond by becoming one with pain. The French are doing now what Americans did in the '70s, not giving audiences a chance to come up for air. I'm not sure which half is more disturbing: the crazy woman stalked and savaged by a "demon" (a figment of her imagination: she's really mutilating herself), while she goes homicidal, or the friend who resumes her place in the hideous seat of torment and gets skinned alive after weeks of unspeakable torture. This film pulls no punches (literally) and has polarized critics with a vengeance.

(3)
The Texas Chainsaw Massacre. 1974. Critical approval:
90%. Fright level: 94/100. I got the ultimate edition DVD for Christmas this year and watched it for the first time in over a decade. It remains a nasty, hard-hitting piece of cinema, which at the same time (believe it or not) relies on Hitchcock-type tricks that make you think you're seeing more massacre than depicted. It isn't close to the bloodbath I remember, but something more disturbing. The classic dinner table scene, involving the only remaining victim strapped to a chair and terrorized by the cannibal-family, is pulverizing. No surprise, the
lousy remake scrapped that scene in favor of cheap prolonged chases through the woods. Stick with the original, which is on almost every top-10 list I've come across.

(4)
Cannibal Holocaust. 1980. Critical approval:
70%. Disturb level: 93/100. An animal snuff film (a turtle, a pig, a coatimundi, a spider, a snake, and a squirrel monkey were killed just as you see them on screen), and the director had to appear in court to prove he didn't kill people as well -- their deaths look that real. (When the film was released, the four American actors had gone into hiding as a ploy, which was perhaps more effective than the director intended.) The narrative is about four college students who go into the Amazon to research bizarre native customs, and get more than they bargained for: forced abortion rites, rape-murder as punishment for adultery, castration, disembowelment, and voracious cannibalism. In the end, they are the victims of this business, and it looks obscenely real. Hailed by many as the most controversial film of all time, and still banned in some countries, it can make you lose your appetite for days; so watch out.

(5)
The Last House on the Left. 2009. Critical approval:
42%. Disturb level: 92/100. Both the original and remake are equally disturbing, but I don't recommend the former because it plays like a snuff film with lousy production values and bad acting. The remake is
surprisingly decent, if flawed, about a group of thugs who kidnap two girls, killing one and raping the other, and then come to the home of the raped girl's parents. The rape scene is the most upsetting that I've seen in any film -- even worse than the longer one in
Irreversible (on which see below) -- not only for the girl's trauma, but for the son of the rapist who is forced to watch and clearly wants to stop his father but can't. The stabbing/torture/death of the other girl is just as intimate and ugly. The whole film radiates an atmosphere of sickening dread, from the initial encounter in the motel room, to the climax in the lake cabin. You feel raped yourself long after the credits roll.

(6)
Eden Lake. 2008. Critical approval:
83%. Disturb level: 91/100. It's Golding's
Lord of the Flies meets
Deliverance meets
Them, and it doesn't add up to a pretty picture. A couple go on a camping trip and run afoul a pack of young bullies. One thing leads to another, until torture and killing are on the menu, and it becomes clear there won't be a happy ending for either Jenny or Steve. The kids' homicidal behavior is so ferocious, and so believable, that it plays like a documentary about U.K. chav culture. It certainly takes nihilism to a new level: the final act involving the parents -- who decide to "take care of their own" and finish what their kids started -- is downright unspeakable. I had trouble picking myself out of the chair after this one. Reviewed at length
here.

(7)
An American Crime. 2007. Critical approval:
31%. Disturb level: 90/100. This film is incredibly hard to sit through, especially knowing it's based on a true account of domestic child abuse. Sylvia Likens was tortured and killed by a woman caring for her in her parents' absence, tied up in a basement for weeks -- beaten, burned, cut, branded, and forced to eat filth, while, amazingly, kids in the neighborhood dropped by daily to participate in the "fun". Ellen Page is as convincing in the role of a savagely abused innocent as she is playing a tormenting sadist (
Hard Candy), if not more so. The final act -- Sylvia's dream of reuniting with her parents as she lies unconscious and dying -- is extremely upsetting. I'm not sure why critics came down so hard on this film; like most of
Ellen Page's accomplishments, it's well done and has a lot to say without being gratuitous.

(8)
Blue Velvet. 1986. Critical approval:
90%. Disturb level: 88/100. When I first saw this back in the '80s it pulverized me. I'd never seen a David Lynch movie and was unaccustomed to suffocatingly dark levels of misanthropy. It's a murder mystery, but surreally weird and vicious, with enough sadomasochism, bullying, and ritualistic rape to make you stop caring about who killed whom for whatever reason. People continue debating whether or not Isabella Rossellini's character is really raped, since she loves being treated violently. I think it has to be rape, because the Dennis Hopper character is able to obtain sex from her only through extortion (having kidnapped her son). The fact that she largely gets off on being brutalized after the fact doesn't negate this starting point.
Blue Velvet is one of the most brilliant cinematic achievements of all time -- rated the fourth best movie of the last three decades by
Entertainment Weekly -- and likewise remains one of the most disturbing.

(9)
Irreversible. 2002. Critical approval:
56%. Disturb level: 87/100. A French film about a woman who leaves a party, walks into a subway tunnel, is raped for an excruciatingly long time and beaten within an inch of her life. Her boyfriend then goes on a mad hunt for the rapist, finds him in a night club and pounds his face in with a fire extinguisher... though it turns out he got the wrong guy. This story is played in reverse, like Christopher Nolan's
Memento, meaning we start assaulted by a chaotic sequence of revenge (but not knowing it's an act of revenge, or who the bad guy really is), moving back to a merciless nine-minute rape scene, and finally to the "happy ending", which is really a happy beginning. The backward structure results in a "fundamentally different film"
(Roger Ebert), because instead of ending with pornographic payoff and revenge, the reverse chronology forces us to think seriously about how we feel during scenes of unbearable violence.

(10)
A Clockwork Orange. 1971. Critical approval:
91%. Disturb level: 85/100. Kubrick's classic is a commentary on crime, violence, punishment, and redemption, but also on the way state authority crushes the human spirit. The famous sequences involve juvenile delinquents who systematically beat the poor and homeless, invade houses of the rich to commit rape and murder, and "singing in the rain" through it all. Kubrick, as always, was ahead of his time in daring to go where cinema hadn't before. To be honest, I've always found the scenes of aversion therapy for rehabilitating criminals to be twice as disturbing as the criminal behavior itself. The attacks of sickness and erosion of free will make capital punishment look humane.
For other "most disturbing" lists, see Greencine parts
one and
two (a top-25),
IGN (a top-15),
Infobarrel (a top-12), and
Alternative Reel (a top-10). I should note that there are films on these lists which would have made my own top-10 if not for the fact that they're completely devoid of artistic merit (
I Spit on Your Grave, the original
The Last House on the Left, etc.).
UPDATE: In response to Stephen Carlson's comment about
Seven, see
Disturbing Thrillers.