I’m going to throw out a bit of an odd-sounding statement here – horror films generally aren’t all that scary. Once you get past the atmosphere and the peril, any errant reminder of the ridiculousness of what’s happening in front of you quickly alleviates the dread, at least for my part.

There’s also the fact that from the beginning, you’re braced for fear. Even if you don’t know what’s coming, that sense of poise and preparation brewing inside you is probably going to keep you from getting especially, distinctly freaked out. When a film completely blindsides you though, it’s a different story. Often, when a non-horror film scares you, it leaves a deeper, far more lasting mark on your subconscious. Beyond just catching you off-guard, it’s usually because they are dealing with subject matter that’s far closer to home than a haunted filing cabinet or a bunch of idiots trapped in a room full of outlandish booby traps.

Now, there are plenty of non-horror films out there which are terrifying for completely unintentional reasons, Willy Wonka and the Chocolate Factory springs almost immediately to mind, but for the purposes of this list we’re doing to stick to the ones that clearly always intended to deal in high-grade fuckedupitude. This also means that, thematically, we’re steering clear of anything that could still loosely be defined as horror. No Silence of the Lambs, no Henry: Portrait of a Serial Killer, no Invasion of the Body Snatchers (but those are all great and you should definitely watch them). The added side-effect of this is that the vast majority of these films match their fear factor with sheer, unbridled misery, so I wouldn’t recommend watching them in rapid succession, since it would probably be tantamount to playing seven minutes in heaven with a dementor.

15. The Machinist

This one could almost make the list purely on the basis of Christian Bale’s appearance. Spending four months on a diet of little more than apples, whiskey and black coffee (and presumably a shitload of cigarettes), he managed to drop his weight down to 120 pounds, or 8-and-a-half stone. He’s 6ft, just to put that into perspective. The role he made this dramatic commitment to play is that of Trevor Reznik (not an accident), an insomniac factory worker whose life seems to make less sense with every passing day.

It’s heavily influenced by Kafka’s The Trial and the work of Fyodor Dostoyevsky, particularly in the way it deals with a slow, cloying descent into madness, which is exactly the kind of soul crushing horribleness that the mad Russian loved to play around with (read The Double if you don’t believe me, then weep for humanity). Through the course of the film Reznik is blamed for an on-work accident, and tormented by a mysterious man named Ivan who nobody else seems to be able to see. It’s scary because it forces you to look through the lens of a person whose every predeliction and concept about how life should work is gradually fading away. You feel for Reznik, but you’re also fearful of what he might be driven to, and unsure if you want to take this journey with him. Director Brad Anderson hasn’t really found much success with any film since, but if you find yourself watching a particularly disturbing episode of The Wire, Fringe or The Shield, chances are he was the culprit.

14. Mysterious Skin

Before Joseph Gordon-Levitt became the dough-eyed, loveable scamp that blew our minds in Brick, tried our patience in 500 Days of Summer and looked nothing like Bruce Willis in Looper, he co-starred in this relentlessly unsettling character drama. From the early stages of the film, you could be forgiven for thinking that it’s going to end up descending into some kind of shlocky, pulpy sci-fi, but the reality ends up being far darker. Levitt and Bradley Corbet play two boys who both have an early, transformative experience as they grow up in a small American town. Brian (Corbet) is harbouring a patchy memory of a supposed encounter with a UFO, whilst Neil (Levitt) has a far more distinct recollection of being sexually abused by his little league coach (although he never attempted to resist the advances, rather, he seemed to welcome them).

Since then Brian has morphed into a paranoid, emotionally subdued shut-in, whilst Neil becomes self-destructively hedonistic, ultimately becoming a prostitute catering to older men who like to screw young-looking boys. Gradually, their paths converge and it becomes clear that both of them were shaped by almost identical forces. It’s a touching film, in some ways, but also a frightening, morally challenging one. It’s the kind of film that takes empathy and almost uses it as a weapon against you. Probably some kind of club with nails in it.

13. Barefoot Gen

Sometimes the most frightening stories are the ones that force you to directly confront something you’ve always known about, but never in true detail. Barefoot Gen is a 1982 anime film based on the manga of same name by Keiji Nakazawa, loosely based on his own personal experience of the Hiroshima atomic bombing. It is perhaps the most vivid, shockingly in-depth visual recounting of any such experience ever made. The actual scene detailing the moment that the bomb hit and the ensuing chaos is only 5 minutes long, but it’s a horrifying hell-scape replete with the kind of imagery that would have Freddy Krueger necking amphetamines to keep from falling asleep.

The aftermath is no better, as young Gen has to cope with the lingering deaths of his mother and infant sister, forever severing any family connection he had left. This film shows what it’s like to look right into the mind of someone who has been through a more traumatic experience than most of us can possibly imagine. There has been no greater single instance of humanity attacking itself than Hiroshima and Nagasaki and this film throws you right into the epicentre of it. It’s unforgettably disturbing but also absolutely vital, from a historical perspective. An extremely laudable recent Kickstarter campaign even set out to print 4000 new copies of the source manga and distribute them around US schools and libraries. This will doubtlessly result in a lot of lost sleep, but justifiably so.

12. Pan’s Labyrinth

When Pan’s Labyrinth was approaching release, you could have been forgiven for thinking it was doing to be a darkly hued, but ultimately uplifting affair about a Spanish girl escaping an unpleasant reality into a beautiful, fantastical alternate one. A latter-day Alice in Wonderland. The idea that anyone would think of it that way now is laughable. That basic plot structure is correct, but neither one of the two worlds we visit during the course of the film has much to offer in the way of comfort or whimsy. The time and place is post-civil war Spain in 1944 (after falling under the fascist rule of the Falange party, lead by Francisco Franco) and the girl is Ofelia.

She’s been taken to meet and stay with her new stepfather, Vidal, a Falangist enforcer and one of the nastiest characters to appear in any film to date. His job is essentially to weed out rebel factions and then do unspeakably awful things to them, and he has no affection for Ofelia (and barely any for her mother, despite the fact that she’s carrying his child). Ofelia then encounters Pan, a mysterious faun from another world, who tells her that she’s actually a reincarnated princess and that, by completing a series of trials, she can reclaim her throne. This turns out to be no easy feat and the further down the rabbit hole she goes, the more awful it seems to get, particularly during the second trial, which tasks her with retrieving a dagger, but culminates in perhaps the most fucked up, terrifying scene in any Guillermo Del Toro movie (and there are a lot to choose from). This film basically outlines the fact that even if you do escape reality, there isn’t anything better waiting on the other side.

11. Dogtooth

Dogtooth is one of those films that walks a fine line between psychological fascination and sheer, petrified revulsion. The sophomore effort of Greek director Yorgos Lanthimos, it tells the story of a family who have gone to great lengths to keep their children almost entirely isolated from the outside world. At the point when we join the film, the children are all approaching adulthood, they don’t have names, speak a language that swaps words and meanings around with sinister intent and no news or knowledge of the outside world ever makes it into the confines of the property. The father uses a combination of fear (mostly of the ‘killer cats’ surrounding the property) and conditioning to push back any desire to go outside.

It is, obviously, a morally reprehensible thing to inflict upon your own children, but an undeniably interesting one. That morbid fascination stays with you as the film delves into the minds of these conditioned children, and what you find staring back at you is so far removed from humanity that it will haunt you for long after. Some of the most meaningful singular shots ever committed to film would be utterly mundane if you removed the context and such is the way with the closing shot of Dogtooth. You’ll never look at a family car the same way ever again.

10. Gozu

Takashi Miike is responsible for some of the most bizarre, mind-bending films ever made in Japan or anywhere else. He’s definitely dealt with horror in the past, but to me, Gozu remains the most consistently frightening film he’s ever made. I’m not certain you can hem it into any particular genre, it’s a cinematic anomaly, fiercely defying classification. It’s the kind of film that seems to hate you, unwilling to ever fully explain itself or comfort you with narrative coherency, you just have to strap in and hope you’re still sane by the end. Supposedly it’s about a man searching for his Yakuza brother, but that setup is so utterly irrelevant by the film’s end that it’s almost not worth calling attention to.

At times it’s almost funny, but invariably at any point when you’re close to laughter something impossibly fucked up is lurking just around the next corner, waiting to pounce. It never ceases to be entertaining, despite only ever offering the most vague parcel of understanding as to what in crikey fuck is actually happening, but as is often the way with Miike films, the most frightening moments are lingering and drawn out, to a torturous extent. If it’s about anything, it’s about the extent and potency of human malice, but by the end all you really want to do is call your Mum and tell her that you love her.

9. Happiness

Happiness is typically categorised as a comedy-drama, and it is funny in places, but in the most soul-cleaving way possible. Any time you laugh at the antics of these desperate people and the awful situations they’re flung between is quickly followed by a moment of pointed self-questioning. It comes from a long line of films which look at the horrors lurking under the surface of the American family formula, think Blue Velvet, or American Beauty. The difference here is that the reality is so terrible that the entire film ends up feeling like a slow-motion car crash.

It follows a series of ostensibly unremarkable characters, but beneath there is a parade of sexual depravity, violence and tragic sadness, and we aren’t spared so much as a drop of it. As you might expect, it all starts bubbling up to the surface and everything completely falls apart. There are arrests, murders and relationships break down left right and centre. It’s scary because it presents all this as if it’s happening right next door to you, this is not the exception, this is the rule. You can laugh, and often you’ll want to cry but ultimately you’ll end up feeling as if normality as a concept has been irreparably damaged.

8. Eraserhead

“In Heaven, Everything is fine – You got your good things, And I got mine.”

Well hello there, David Lynch, you took your time, didn’t you? Making films that are not ostensibly horror, but are nonetheless potently frightening is basically Lynch’s bread and butter. I could have filled this list with his work but I decided to only include two of his most unsettling works. If we were covering TV you’d certainly find Twin Peaks knocking about.

Eraserhead remains his most bizarre film, if not his most disturbing, but it’s close. Set primarily within the subconscious of a man named Henry as he struggles to cope with real world issues, this is a film of overwhelming atmosphere and alarming obscurity. There’s meaning behind all of it, but it can be difficult to immediately grasp that meaning when you’re busy recoiling from the screen like a frightened rabbit. The pervasive, industrial sound design, the sparseness of spoken dialogue, the claustrophobic setting and the shocking body horror all work in unison to create something uniquely visceral and profoundly terrifying. It’s a tactile film, using contact and movement in a way that evokes a kind of weird primal empathy, you can almost feel your nerve endings tingle as you watch it. You find yourself nervously poised for some kind of grand, energised payoff, but one never arrives and you’re left to muddle through it all without anything close to a hand to hold. Perhaps just a shrivelled, mutated little claw.