View source for Through the Eyes of Madness

{{trope}}{{Needs Image}}
{{quote|''Yesterday upon the stair''
''I met a man who wasn't there.''
''He wasn't there again today''
''Oh how I wish he'd go away.''
|'''Hughes Mearns'''}}

Life is going good. Oh, okay — you might be a little stressed out or a little down in the dumps but it's nothing serious. Then things start going wrong. You see a face on the outside of a ten-story window; an imposter seems to be taking your place at home; the same white-eyed man keeps watching you from a distance; a tramp gives you proof that your neighbour is a demon, but the proof disappears soon after (as does the tramp).

You try to gather proof, you try to convince your wife, but she doesn't believe you. None of them believe you. They say you're crazy, but you're not crazy. Not at all. It's ''them'' making everyone think that. And they replaced your wife with one of ''them'', so you had to kill it. You wouldn't kill your wife, would you? Would you? Of course not. It's all real. It has to be, because otherwise you'd be seeing '''Through the Eyes of Madness'''.

The creepy, foul-smelling uncle of the [[Cuckoo Nest]], Through the Eyes of Madness makes a point of obscuring the objective truth of the tale in order to [[Mind Screw|screw with the audience's minds]]. Sure, ''we'' see the grotesque tendril moving under the neighbor's skin just like the protagonist does, but who says the camera is telling the truth? Then again, there's never any conclusive proof that he's ''not'' a monster either. By their very nature, these stories end without any definite decision as to what was ''really'' going on.

Compare to [[Only Sane Man]]; in it the Only Sane Man, along with the audience, is sure that the strange thing is real and everyone else just turns a blind eye on it, while this leaves it ambiguous. Another key difference is that trope is often used for comedic effect while this trope is horrific if done properly.

Unlike the [[Cuckoo Nest]], there isn't an "either/or" pair of realities that can be switched between, or a ''truthful'' reality waiting to be accessed—just [[Nightmare Fuel|a long, horrible descent into the darkness of the human mind]].

Compare [[Unreliable Narrator]], for instances in which this character is telling the story. Is often [[Paranoia Fuel]] at its purest, if done well. Contrast [[Maybe Magic, Maybe Mundane]]. If madness gives a person the ability to see real things that others can't, that's a variety of [[Power Born of Madness]].

If it's clear that it's not all in the protagonist's mind and the danger is real, then the main character is [[Properly Paranoid]]. If the madness conceals the fact that the protagonist is a murderer, that's [[The Killer in Me]].

'''Expect some spoilers here. In many works, the fact that the viewpoint character is crazy is a major [[Twist Ending]].'''

{{examples}}
== Anime and Manga ==
* ''[[Paranoia Agent]]'', a series directed by Satoshi Kon, starts off here, with the existence of Lil' Slugger and the sanity of the witnesses and/or victims in extreme doubt. When incontrovertible proof is presented that Lil' Slugger is {{spoiler|real - but not a real ''person'' - and he is most definitely supernatural,}} that's the signal for things to ''really'' go off the rails.
* Another of Kon's works, ''[[Perfect Blue]]'', has this among the many tricks it plays with perception and reality. Towards the end, the audience is seeing things through the eyes of ''two'' different characters' madness, at the same time.
* ''[[Paprika]]'' is another example. Once again, it's made by Satoshi Kon.
* A significant portion of the first season of ''[[Higurashi no Naku Koro ni]]''. It doesn't help that sometimes it's a [[Unreliable Narrator|first-person narrative]] at the time. Although some objective explanations are given. Eventually. However, a good chunk of the explanations are only [[All There in the Manual|in the visual novels]].
** Masterfully done in Tatarigoroshi-hen. In order to protect Satoko, Keiichi kills her [[Evil Uncle]]. But the next day, Satoko insists that her uncle abused her later that night and his other friends say Keiichi was at the festival at the time. But wait! The uncle's missing and the body isn't where Keiichi buried it. Satoko still insists that her uncle is abusing her. {{spoiler|Keiichi ''did'' kill Teppei and everyone's providing a cover story. Why does Satoko insist Teppei is still alive? Well... Just because Keiichi is the [[Unreliable Narrator|Unreliable POV Character]] doesn't mean he's the ''only'' one going crazy, does it?}}
** Also ''[[Umineko no Naku Koro ni]]''—no witnesses survive the murders, but the audience is shown the spectacularly magic action sequences. Whether those could be possible or not depend on the viewpoint of the character (and the anime at least left that inconclusive.)
* ''[[Ghost in the Shell]]'' has one of these. {{spoiler|An assassin is interrupted by the protagonists, but blows himself up to take out his target}} Well, actually not. That minute of footage was all from his viewpoint, so he only thought he pulled it off. It's subtle to catch too, reading the revealing line wrong makes it look like there was some [[Deus Ex Machina]] going on.
** There was another episode focusing on a pilot fantasizing about assassinating his politician boss. It opens with a shot of him succeeding, then cuts to reveal that they hadn't gotten to the destination that it took place in. The main characters are randomly different people, apparently running a brothel. At the end, they agree that he's not a real threat to anyone's life, as he would never really go through with his assassination plot.
* In ''[[Soul Eater]]'', the effects of the Kishin and the Black Blood are an erosion of sanity. Since {{spoiler|the good guys failed to stop the Kishin from reviving, the effect is slowly spreading over the entire world.}}
** For examples, there's the kids hallucinations when they come face-to-face with Asura, Eruka and Free having the skin ''pulled off their faces'' plus the one where Black Star appears to succeed in stopping Eruka. Maka's hallucination in the Clown chapters is just cruel.
* ''[[Chaos;Head]]'' features a main character who is a self-described disgusting, delusional, [[Otaku]], [[Hikikomori]] who is approached by [[Harem Genre|several beautiful girls]] all with a mysterious connection to a series of murders going on in Shibuya. This makes it extremely hard to tell where the events of the series lie on the line between paranoid hallucination and supernatural strangeness—if there is in fact any separation between the two at all.
** As it turns out, the main character himself {{spoiler|is the equivalent of someone's [[Imaginary Friend]] taking a life of his own and turning into a [[Not-So-Imaginary Friend]]. The "real" Takumi is a wheelchair bound old man with a terminal illness. The teenaged, otaku Takumi is the result of the "original" Takumi's near [[Reality Warper]]-level ability to project "illusions". The delusions that Takumi experiences are likely linked to his nature as a [[Tomato in the Mirror]], and not because he's suffering from a lack of sanity.}}
* ''[[Boogiepop Phantom]]'' plays out like this for the first few episodes(and probably longer than that even...) as most of the time the viewer's in [[Mind Screw|WTFland]] trying to figure out what's real and what's not. Is that guy eating bugs for reals or is it just a sick illusion?
* The final episodes for ''[[Neon Genesis Evangelion]]'' definitely qualify. Were the events of the last two episodes real, or were they all merely taking place in Shinji's shattered psyche?
** From a literal standpoint, they could have potentially fit in during the closing moments of the movie. Aside from a few completely minor details, the two endings are basically compatible with each other. Depending on your interpretation, of course.
* In ''The Horror Mansion'', the story "The Magic Ball" has an ugly scene at the end that shoves the entire story firmly into this camp. {{spoiler|Despite previously seeing the hand of Atsuko's baby, indicating that it was a normal human child, we now see it as a monster, just like Mayako's babies... while Atsuko seems to see all the babies as normal. As Atsuko never seemed to have been affected by whatever the Magic Ball had done, this raises the possibility that our vision of the babies as monsters into doubt. And if we can't trust what we see or read to be what really happened here, how can we know that any of the apparent strange happenings throughout the story were real? The monsters in the well, Isamu's transformation, the bizarre change in attitude of Mayako and Atsuko's parents... it's possible none of it was real.}}

== Comic Books ==
* ''[[The Filth]]'', written by [[Grant Morrison]], is deliberately ambiguous about how many of the events are real and how many of them are Greg Feely's encroaching madness.
* The events of ''Mnemovore'', a [[Cosmic Horror]] [[Comic Book]], may be just the main character's fractured memories.
* In ''[[How Loathsome]]'', Nick—a drug dealer—tells a story of how three German men followed him around, using mind-control powers to mess with his perception until he shot them dead. How much of this was a hallucination caused by drugs, how much is the truth and how much is a lie is never explained.
* ''[[The Killing Joke]]''. Joker's flashbacks.... [[Multiple Choice Past|Are they what actually happened or simply a fabrication of his twisted mind?]]
* [[Scott Pilgrim]] and Gideon Graves both subconsciously create false memories so they don't have to live with their mistakes. The false memories they come up with are kind of... weird.
* Whenever [[Deadpool]] is the main character or narrator. His main series that debuted in Secret Invasion is a great example, mainly the first issue showing him seeing the people trying to kill him as admiring fans wanting an autograph. He snaps out of it, but it makes you wonder just how reliable his point of view actually is. I mean, ''he thinks Nick Fury is a talking baby.''

== Film ==
* Thanks to [[Executive Meddling]], ''[[The Cabinet of Dr. Caligari]]'' becomes this.
* The realization that Nina from ''[[Black Swan]]'' is batshit insane puts an interesting spin on much of the rest of the movie.
* The film from which this trope previously took its title, ''[[In the Mouth of Madness]]'', was heavily inspired by the [[Cosmic Horror]] of HP Lovecraft and featured Sam Neill going mental with an axe. To make it even better, the question isn't just limited to whether Sam Neill's character is sane or not, but also whether he actually exists or is just a figment of the in-story horror writer's imagination (or for that matter, a figment of the screenwriter's mind). The man's not just in the mouth of madness, but ''being digested''.
* ''[[The Amityville Horror]]'' is one of the best examples, especially the remake. The protagonist becomes posessed by the haunted house, seeing his own children (and wife) as demons and eventually [[It Was His Sled|killing his own dog with an axe!]] Later on he goes after the family too, but {{spoiler|after being knocked out and dragged away from the house, he becomes sane again.}}
* ''[[The Machinist]]'' is an almost surrealist example of this trope. However, the ending revelation rationalizes everything.
* ''[[Jacob's Ladder]]'', where the main character can't tell whether he's really switching back and forth between realities, or if the hellish experiences and the crazy [[Government Conspiracy]] he thinks he went through are just the products of his feverish mind. {{spoiler|It turns out he's [[Dying Dream]] and/or [[Dead All Along|in purgatory]], and all the awful things he goes through are helping him let go of his life.}}
* ''[[Videodrome]]'' (1983), written and directed by [[David Cronenberg]].
* ''[[Naked Lunch]]'' (1991), by director David Cronenberg.
* ''[[eXistenZ]]'' (1999), written and directed by David Cronenberg. Noticing a trend here?
* ''[[Vanilla Sky]]'' (2001), directed by Cameron Crowe and starring Tom Cruise. Remake of 1997 Spanish film ''Abre los Ojos'', a.k.a. ''Open Your Eyes''. After a car accident that kills his girlfriend and disfigures his face, the protagonist is haunted by increasingly bizarre occurrences. The ending explains that {{spoiler|everything that has occurred after the car accident has been a dream. In real life, after the car accident, he signed a contract with a company that preserves its clients' bodies after death and keeps their brain waves active in lifelike virtual reality dreams, and then committed suicide. The bizarre occurrences are explained as glitches in the program. In the end, he decides to wake up from the dream program.}}
* Roman Polanski's ''[[The Tenant]]'': the protagonist (played by Polanski) learns that the previous tenant of his apartment had committed suicide by throwing herself from the apartment window; he becomes convinced that his neighbors are trying to force him to re-enact her suicide. By the end of the film, it is unclear how much of what we have seen has been the product of his descent into madness.
* Since ''[[The Descent (film)|The Descent]]''{{'}}s main character was hallucinating without a doubt at several separate points, there is a popular theory that the cave monsters were all in her mind and it was her that {{spoiler|killed all her friends}}. The director originally put a crawler silhouette into the first hallucination sequence (which took place outside the cave) but had it edited out because he wanted to leave it more ambiguous.
* ''[[A Tale of Two Sisters]]''.
* ''[[American Psycho]]'' seems just about plausible as a conventional serial killer movie—until the [[Villain Protagonist]] goes to withdraw money from an ATM and it displays a message that he finds perfectly reasonable: "{{spoiler|FEED ME A STRAY CAT.}}"
* One popular interpretation of ''[[Drag Me to Hell]]''.
* The American remake of ''[[Dark Water (film)|Dark Water]]''. While the mother's neuroses and [[Unreliable Narrator|unreliable point of view]] exist in both versions, the finale of the original cements the [[Our Ghosts Are Different|ghost horror story]] interpretation while the remake [[Adaptation Distillation|prefers to leave it ambiguous]].
** The original Koji Suzuki short story just about counts as this trope, too. Yoshimi experiences several minor paranormal occurrences, and at the end is unsure whether it was real or the product of her over-stressed mind.
* As might be expected from [[Mind Screw]] master [[Philip K. Dick]], ''[[Total Recall]]'' plays with this: the film never resolves (and actively makes hazy) whether Quaid actually experiences the film's events or imagines it all due to his brain being monkeyed with at Rekall.
* ''[[Antichrist]]''. Maybe one of the protagonists is crazy. Or maybe both are. Or maybe there really is ''something'' in the woods. [[Mind Screw|Or maybe all of the above simultaneously]].
* The whole * point* of the film ''[[The Shining]]''. The only telltale sign that it's supernatural is the [[Indian Burial Ground]].
** That's not the only sign: there's also the scene where {{spoiler|someone or something lets Jack out of the locked storage room}}, the scene where {{spoiler|Danny manages to call Hallorann for help using his psychic powers, even though he's hundreds of of miles away}}, and the final shot of the movie. None of these can be explained by assuming the protagonist(s) are crazy.
*** Some of the "hallucinations"—such as the waves of blood pouring out of the elevators—don't appear to have any character imagining or "watching" them. (Which could be [[Handwaved]] somehow, but...still, it's creepy.)
* ''[[The Infernal Affairs Trilogy|Infernal Affairs III]]'' turns out to be this at the end.
* ''[[Shutter Island]]'', in it the protagonists viewpoint becomes increasingly inconsistent, until the halfway point where we are first forced to consider the possibility that he is the one who is truly mad.
* Roman Polansky's "Apartment Trilogy", consisting of ''[[Rosemary's Baby]]'', ''Repulsion'', and ''The Tenant''.
* ''[[Il Profumo Della Signora in Nero]]'' chronicles the descent into complete insanity of a woman due to the childhood trauma of {{spoiler|having [[Driven to Suicide|driven her mother to kill herself out of shame]].}}
* ''La Moustache'', a minor French film, uses this to a smaller degree. First the protagonist shaves off his moustache, and his wife doesn't remember he ever had one. He finds photos of a vacation they took, and in the photos he had a moustache, but the photos disappear, and his wife doesn't remember ever taking the trip. {{spoiler|Then he tries to call his mother and finds out she's been dead for a year, and his wife tries to have him institutionalized and forcibly medicated. He escapes and flees to another country, gets a hotel room and wanders around for a while--then returns to the hotel room and discovers his wife's there, and thinks they're on vacation together. She doesn't remember any of his previous confusion, and the viewer is confused in turn.}}
* ''The Hand'' wherein the protagonists severed hand goes around killing people. {{spoiler|Turns out it was him all along doing it because the trauma of losing his hand and finding out his marriage is very unstable drove him insane.}}
* ''[[The Uninvited (2009 film)|The Uninvited]]'', though it's executed with very little ambiguity.
** Done ''way'' better in the original, ''[[A Tale of Two Sisters]]''.
* 'Spiral', which leaves several questions up in the air at the end. {{spoiler|Did he kill all of these women? Did most of them actually exist? What's the final sketch?}}
* ''[[Inland Empire]]'', like most of the movies of David Lynch, starts in a somewhat "realistic" way, but after the first hour, is practically impossible to know what thing is real, a dream, or hallucinations.
* The war of wills between the title character and the housewife in [[Peter Weir]]'s ''The Plumber'' has some elements of this. Certainly, the plumber does behave in ways that are completely inappropriate and occasionally illegal, but the film keeps it deliberately vague as to whether he's a genuine psycho who is menacing this poor woman, or she's a neurotic who is projecting her anxiety onto a harmless oddball.
* In ''[[Don't Look Back (film)|Don't Look Back]]'', the viewer sees things from the point of view of main character Jeanne, who increasingly comes to doubt her own sanity as the film progresses.
* In ''Summer Of Sam'', there's a scene of David Berkowitz being ordered to go out and kill people by his neighbor's demon-possessed dog. (Also a [[Did Not Do the Research]], as the real Berkowitz eventually admitted he'd made up the demon-dog story when he was bucking for an insanity defense.)
* In the original version of ''[[Cat People (film)|Cat People]]'', whether the wife was ''really'' turning into a vicious beast or was just plain nuts was left heavily ambiguous.
* In ''Clean, Shaven'' the protagonist is a man suffering from schizophrenic, and it uses abstract images and sounds to show what he is experiencing.
* David Cronenburg's ''[[Spider (film)|Spider]]'' is also about a man with schizophrenia who is reliving the traumatic events of his childhood.

== Literature ==
* The book ''[[The Turn of the Screw]]'' and its film adaptation, ''[[The Innocents]]''; whether or not the children are really being haunted is never addressed.
* Potentially most or even everything by [[Franz Kafka]]. ''The Trial'' and ''The Metamorphosis'' standing out as very good examples.
* Rachel Klein's ''[[The Moth Diaries]]''... You never figure out how much was hallucination, or whether it was indeed hallucination at all.
* ''[[A Scanner Darkly]]'' by [[Philip K. Dick]]. The protagonist has increasing trouble in making the distinction between reality and fantasy, due to his addiction to a drug that causes a split between the two hemispheres of his brain.
** This is a favorite trope of [[Philip K. Dick]] and variations appear in most of his works.
** PKD ''lives'' on this trope (this and [[Paranoia Fuel]]). ''VALIS'', anyone? ''Flow my tears the policeman said'', ''Game players of Titan'', ''Ubik''... hell. Pick any of his novels or short stories and you will find a protagonist spiraling into either the terrifying deconstruction of his own mind, or the painful deconstruction of reality. Either way, said protagonist is going to be royally screwed.
*** ''A Maze of Death'' isn't as well-known (understandably, due to its inconsistent publication history), but it's a pretty good rehearsal of the themes [[Philip K. Dick|PKD]] would soon explore in more detail in ''Ubik''.
* ''[[American Psycho]]''. Patrick Bateman, the narrator, is clearly insane, and has bizarre hallucinations (such as a Cheerio interviewed on a talk show, or himself stalked by a park bench) which he believes to be true. It's also ambiguous whether he committed the brutal (and somewhat unlikely) murders that he describes in graphic detail.
* ''[[Lunar Park]]''. The narrator is a writer named after the author of the novel: [[Bret Easton Ellis]] who is an unreliable narrator, because he describes things the other characters don't see or feel. The main character is abusing drugs, some of the hallucinations might be to some extent related to that. Also there is a intertextual reference to Ellis novel American Psycho. Ellis' character has apparently also written a novel titled American Psycho and he says: "Patrick Bateman is an unreliable narrator."
* Germain, from Eric Nylund's ''[[A Game of Universe]]'', has multiple personalities. However, he knows he has them (and can usually keep them in control) and there's a valid source for them: a magical ritual to copy knowledge from someone. However, when he learned the ritual no one mentioned the voices-in-your-head side effect, and coincidentally he doesn't start hearing them until after some incredible traumatic experiences. By the end of the story, two characters have suggested that he didn't actually copy their personalities into his head, he simply made them up in order to justify doing certain unpleasant things (however one of the characters advancing this idea lives in his head, and the other is a [[Mind Screw]]ing telepath).
* ''[[Shutter Island]]''. Saying more about it would just spoil it, and it's worth reading.
* [[Stephen King]]'s ''[[The Girl Who Loved Tom Gordon]]'' plays this trope with one aspect. The creature that stalks Trisha, and eventually confronts her at the book's climax: is it just a black bear, distorted by her fear and her fever-induced hallucinations? Or is it really the supernatural horror, the "God of the Lost" she imagined it to be as it stalked her, and during her mental duel with it? Just to toy with you, the novel has someone else witness it who seems to provide the objective truth of it being a black bear... then it turns out he thought it was something else for a moment, too, ''and'' he's a drunk and no more reliable.
** This comes up again in his short story ''The Moving Finger'', in which a man believes that he sees a finger sticking up out of his bathroom sink's drain. Things get increasingly weird (and the main character gets increasingly unhinged), until the reader isn't sure what's really going on. The ending suggests one possible 'mundane' explanation, but leaves it ambiguous.
*** This story can also be read without doubting the narrator, and either way the very end seems to be designed to suggest that it was all real.
** Stephen King explores and discusses the trope more extensively in his non-horror short story ''The Ballad of the Flexible Bullet''. A writer is told a story by his publisher about another writer, struggling with writer's block, who became obsessed with the idea that his typewriter was inhabited by beings who were truly responsible for his writing quality, beings who needed to be appeased with offerings for his continued success. The protagonist indulges what seems like a harmless superstition by leaving an offering for the "Fornits", and gradually spirals into the same delusions. The climax in particular implies ''either'' that the writer was either actually right, '''or''' had managed to thoroughly delude his wife who had, up until that point, seemed to be a non-believer.
** King said that the appeal of ''The Shining'', for him, was the way that it "blurred the line between the supernatural and the psychotic"—although it seems less blurry than in Kubrick's film version.
** King also does this in his short story "Suffer the Little Children", in which neither the teacher nor the readers are sure if her students are "something else" or not. They seem to confirm their identity to her, but who knows if the words the teacher hears are what was really said?
* [[Nick Cave]]'s ''And the Ass Saw the Angel'' is really clever about this. The book quickly establishes the setting as a [[Magic Realism|Magic Realist]] one. But then the protagonist turns out to be a pretty [[Unreliable Narrator]], and we're left wondering how much is in his head.
* Truman Capote's short story Miriam tells the story of a little girl taking over a middle aged woman's life. Except that the little girl exists only in the woman's head.
* In ''[[House of Leaves]]'', Johnny describes in detail how the Minotaur attacks and rips into him, or how he vomits at its stench, only it didn't happen and the creature was never there in the first place. Or was it? The book is [[Mind Screw|irritatingly vague]] about whether the creature exists or Johnny is hallucinating. For certain, Johnny descends further and further into insanity as the book progresses.
* ''Young Goodman Brown'', by Nathaniel Hawthorne, uses this. Goodman Brown is walking into a forest with the devil to a witch's meeting, at which he sees all the good and prominent people of his Puritan township in unholy worship. He ultimately rejects the devil and the whole thing disappears, leaving the reader and the character unsure of whether or not what he had seen was real. The lack of surety and the constant doubt poison Goodman Brown until he finally dies as a twisted, suspicious, lonely old man.
* [[The Reveal]] in ''[[Evil Genius Trilogy|Evil Genius]]'' starts out sounding like Cadel is simply paranoid, but then the evidence starts stacking up...
* ''[[The Yellow Wallpaper]]'' describes of a woman who's locked in a room with only the yellow wallpaper to look at, growing more obsessed and insane about it as time goes on. It's semi-autobiographical.
* Several of [[H.P. Lovecraft]]'s stories (notably "The Rats in the Walls") read in this fashion, it often never being quite clear whether what's happening to the characters is actually happening, actually happened, or whether the characters just went insane. The fact that many of them start off clearly not that well adjusted in the first place and even more of them wind up in an insane asylum or living deep in [[Paranoia Fuel]] Territory really doesn't help things.
* ''[[Dracula]]'' has a couple long stretches that read like this. Notably, Jonathan's diary entries get like this, especially if read taking into consideration exactly how his sense of time passing has been screwed up. It's definitely a viable [[Alternate Character Interpretation]] that the main cast are all pretty cracked.
* The terrifying "The Repairer of Reputations" in [[Robert W. Chambers]]' ''[[The King in Yellow]]''.
* In the book ''[[The Devil's Advocate]]'', this is much more present than in the safe Hollywood'esque film, to the point of getting seriously disturbed as {{spoiler|the protagonist kills his boss.}}
** The movie did have a little of its own mind screw version of this though...
* [[Edgar Allan Poe]] is a master of this, especially in ''The Tell-Tale Heart''. *shudder*
** He's also the master of the sarcastic deconstruction of this trope.
** [https://web.archive.org/web/20130524021206/http://classiclit.about.com/library/bl-etexts/eapoe/bl-eapoe-haunted.htm The Haunted Palace.] [[World of Symbolism|It's not]] [[Driven to Madness|about]] [[Fridge Horror|a palace]].
* "The Horla" by [[Guy de Maupassant]] is exactly that. As is almost any fantastic short story written by de Maupassant. And the author himself ended his life in a psychiatric hospital.
** By the way, "The Horla" actually ''inspired'' "The [[Cthulhu Mythos|Call of Cthulhu]]". [[H.P. Lovecraft|HP Lovecraft]] praised it, and said:
{{quote|"Relating the advent in France of an invisible being who lives on water and milk, sways the minds of others, and seems to be the vanguard of a horde of extra-terrestrial organisms arrived on earth to subjugate and overwhelm mankind, this tense narrative is perhaps without peer in its particular department." }}
* The apparently boring narrator of Sarah Waters' ''The Little Stranger'', who may or may not be responsible for all the horrible things that happen—including {{spoiler|the suspicious death of his ex-fiancée.}}
** Waters' earlier novel ''Affinity'' also featured a first-person narrator sliding into insanity, though there it's made quite clear at the end what's actually going on.
* The short story ''A Pursuit'' by Brian Evenson. The narrator describes how for days he's been pursued by his third ex-wife, or maybe it's his second ex-wife, while sometimes interrupting himself to give a [[Suspiciously Specific Denial]] about the death of his first ex-wife or to criticize himself for [[Breaking the Fourth Wall]]. While the ending is very open to interpretation, it implies that {{spoiler|he had already murdered all three of his ex-wives before the story began}}.
* In [[Dean Koontz|Dean Koontz's]] ''[[Odd Thomas]]'', this is partially used in the fact that {{spoiler|it's made to seem that Stormy lives through the mass murder at the mall, when instead it's just Odd's ability to see dead people fooling the reader into thinking she's alive. Odd even says, "For a while I had gone mad."}}
* In ''The Terror'' by [[Dan Simmons]] it's not clear if the monster slaughtering the explorers is just a combination of sleep deprivation, denial, stupidity and a bear or if it is actually the spirit Arctic.
* ''[[One Flew Over the Cuckoo's Nest]]'' is narrated by "Chief" Bromden, a paranoid schizophrenic who hears machinery clanking in the walls, sees his fellow patients controlled like marionettes by Nurse Ratched, and repeatedly claims the entire ward is enveloped in a thick white fog that makes it impossible to see or move. At the beginning he claims that everything he describes "Is true even if it didn't happen."
** His narration doubles both as a terrifyingly astute metaphor, and a description of his own view of a reality that was long ago fucked over.
* A version of [[Hans Christian Andersen]]'s ''The Emperor's New Clothes'' featured in one of the Datlow/Windling [[Fable Remake]] collections plays a relatively lighthearted version of this. Due to a twist involving the boy who reveals that the Emperor has no clothes, both the narrator (The brother of the Emperor, who is a manipulative, treacherous would-be usurper who's far more incompetent than he realizes) and the reader are left wondering whether the clothes didn't exist, or they really ''did'' exist, and the narrator couldn't perceive them because he was wholly unfit for his position.
* In [[Larry Niven]]'s story "The Ethics of Madness", the protagonist unknowingly [[No Medication for Me|goes off his meds]] because his autodoc's "refill me" light burns out just as the drug supply is exhausted. Once, he uses another autodoc and gets re-medicated... and when it wears off, he "realizes" that the other autodoc had been tampered with by his "enemy". Not surprisingly, [[It Got Worse|things go downhill from there]].
* The ''[[Doctor Who]]'' [[Eighth Doctor Adventures]] novel ''The Blue Angel'' is a less-disturbing variant than most: the [[Alternate Universe]] human Doctor has already been diagnosed as mentally ill, generally doesn't take his delusions too seriously, and generally stays on his meds, so it seems that he's unlikely to become too terribly confused. However, it does render the story very confusing, especially as some of the things he has delusions of certainly seem to be actually happening in one of the story's [[Four Lines, All Waiting|other plotlines]], and the reader really can't tell if the story contains [[Magical Realism]] or the Doctor simply hallucinates that his mother is a mermaid, one of his friends has a talking dog which tells his other friend that all realities and stories are equally real, and other strange things. It also creates the impression that perhaps the TV series is basically [[All Just a Dream]]—the Doctor just has delusions about Daleks and Cybermen and [[Freud Was Right|weird phallic monsters]] [[Special Effects Failure|made of cellophane]] and such.
* [[Nikolai Gogol]]'s appropriately titled short story, "[[Diary of a Madman]]", chronicles the descent into madness of a [[I Just Want to Be Special|petty]] [[Tsarist Russia|Russian]] bureaucrat who eventually comes to the conclusion that he is [[Napoleon Delusion|the heir to the throne of Spain]].
* [[Stanislaw Lem]]'s character Ijon Tichy is subject to this in ''[[The Futurological Congress]]'' after being dosed with powerful hallucinogenic drugs.
* Patrick McGrath, author of Spider and The Grotesque, seems to be fond of this trope.
* This trope is the ''only'' possible explanation for the [[Mind Screw]]y ''[[Goosebumps]]'' book ''I Live In Your Basement'', about {{spoiler|a boy named Marco who defies his overprotective mother and goes out to play baseball, only to get hit in the head. While recuperating, he receives strange calls from a boy named Keith, who lives in his basement, and is said to be a blob monster disguised as a human. The rest of the story shows how Marco's reality is slowly slipping away and how everything he experienced is either a dream or a vivid hallucination -- until it's revealed at the end that Keith is the one having the weird dreams and that he's the one who lives in fear of the human who lives upstairs}}.
* Possibly one of [[Charles Dickens]]' most chilling ghost stories is titled "A Madman's Manuscript" (from ''[[The Pickwick Papers]]''). There are a lot of exclamation marks.
* Barry N. Malzberg's short story ''What I Did to Blunt the Alien Invasion''. This story has two tracks, one in which aliens reveal themselves to a man and warn of a coming invasion, after which he does everything within his limited means to warn people, including {{spoiler|offering to betray humanity}}. The other is implied to be a man who becomes unstable, eventually causing his wife to leave and he to be arrested.
* ''The Double: A Petersburg Poem'' by [[Creator/Fyodor Dostoyevsky|Fyodor Dostoyevsky]] fits this trope.
* Alexandre Dumas' ''[[The Woman with the Velvet Necklace]]'' establishes early on that is viewpoint character comes from a family with a history of mental illness, and that he himself hasn't always got the stablest relationship with reality. Later, even the viewpoint character is tortured by the questions, is he going insane? Is he a recent escapee from a mental hospital? Or is the story that he's a recent escapee from a mental hospital merely a coverup for a story that is far more bizarre and horrifying?
* The premise of Sheridan Le Fanu's short story "Green Tea". Is Rev. Jennings really being visited by a demonic monkey that no one else can see? Or is the green tea he drinks habitually slowly poisoning him, causing visual and auditory hallucinations? The story's narrator insists it's the latter, and is confident he can cure Jennings, but  {{spoiler|before he gets a chance to try, Jennings kills himself under the monkey's orders.}} It's made doubly tricky via its use of the [[Literary Agent Hypothesis]]: the story's "editor" freely admits to having changed the names of all the characters save for the protagonist, and tweaking and omitting bits of information here and there - but nevertheless insists he is [[Blatant Lies|completely impartial]].

== Live-Action TV ==
* A seventh-season episode of ''[[CSI]]'' danced around this trope, when the team gets to deal with a cult that believes in an [[Ancient Conspiracy]] of shapeshifting snake aliens. One of the cultists is under interrogation, and at one point we see the detective raise his water glass and, without warning, dip a snake-like tongue into it. Of course, this being ''[[CSI]]'' and not ''[[The X-Files]]'', this was only a hallucination of the cultist. {{spoiler|Probably.}}
* Subversion: the ''[[Star Trek: Deep Space Nine]]'' episode "Whispers", where everybody Miles O'Brien knows slowly turns against him. {{spoiler|The subversion is that it is Miles O'Brien himself who has been replaced, and the story is told from the clone's point of view. He [[Tomato in the Mirror|doesn't know this]], but everybody else does (or learns). Both he and the audience only find out at the end.}}
* In the episode "Persistence of Vision" on ''[[Star Trek: Voyager]]'', Janeway is starting to see parts from her holodeck program in different parts of the ship. They go from little things, like being served the same meal as the one she saw in the program, to characters talking to her. It finally culminates into one of them attacking her in her quarters. She wrestles the attacker down and calls for security. Just as you're wondering what's taking security so long to get there, the camera shifts and it turns out she's in sickbay, having never left after her initial exam in the first place.
* Played straighter in the episode "Frame of Mind" of ''[[Star Trek: The Next Generation]]'', where something like this happens... well it's safe to say the episode was about Riker. Maybe.
** Also in the TNG episode "Remember Me", everyone on the ship begins to vanish, with Doctor Crusher the only one who remembers their existence. Once she's the only person left on the ship, the rest of the universe begins to disappear as well, to the point where, when she asks the computer the nature of the universe, it has an answer, and specifically that the universe is only the size of the ship.
{{quote|'''Crusher:''' If there's nothing wrong with ''me'', maybe there's something wrong with the ''universe''.}}
* A particularly creepy episode of ''[[Stargate SG-1]]'' (3x04 "Legacy") has Daniel Jackson slowly going insane from delusions and terrifying hallucinations caused by a piece of [[Applied Phlebotinum]]. Much of the episode is seen from his perspective, resulting in this trope. At the halfway point, however, it turns into a [[Cuckoos Nest]] trope when the other characters find proof that Daniel was never actually insane as such. The episode would have been more effective if we, the audience, hadn't been shown ''some thing'' infecting Daniel's body right in the first act of the episode.
* A ''[[Stargate Atlantis]]'' episode (3x06) had Weir wake up in an asylum and be told that she had hallucinated the entirety of her time on Atlantis as a way of coping with her fiance's death. The doctors urge her to let go of her delusions to become sane again. In reality she has been infected with replicator nanites that are causing her to hallucinate the asylum.
* One of ''[[The X-Files]]'' episodes ("Field Trip") has Mulder and Scully trapped underground in a giant fungus mycelium, hallucinating that they were trying to solve a case (the case that brought them into the forest, in fact), while in reality the mycelium was secreting a hallucinogenic narcotic compound onto their skin to keep them passive while it slowly digested them.
** To further fit this trope, both Mulder and Scully seem to have had the exact same "plot" to their hallucinations, which is pointed out as impossible in the actual episode.
* The ''[[Criminal Minds]]'' episode "Normal". A man takes out his fantasies of killing his family by killing other people. This leads up to a climactic chase scene where he's trying to get his family out of the city when his wife jerks the wheel and makes them crash. When he's pulled from the rubble, it's revealed he {{spoiler|had been hallucinating them the whole episode and killed them pretty early on}}, which is hinted at constantly, in retrospect. It's one of those things you've got to watch twice.
* The [[Lonely Island]] song/''[[Saturday Night Live]]'' Digital Short "Like a Boss". The "boss" is clearly unstable, and it's possible the hallucinations start after he fails suicide, but after he blacks out in the sewer, it falls into [[Talkative Loon]] territory.
* ''[[Buffy the Vampire Slayer]]'' Season 6: A demon stabs Buffy with a weapon that it is a part of it. Said weapon is also poisonous and causes vivid hallucination. Buffy believes she is in an asylum being treated for her delusion that she is the Slayer. After 6 years of watching the show, we the Audience automatically assume that the Sunnydale scenes are real and the asylum scenes are delusion until the final reveal, which has one final "hallucination" that she's gone catatonic.
* In the ''[[House (TV series)|House]]'' episode "No Reason", House is shot and is placed into a drug-induced coma. When he wakes up, his debilitating limp is cured, but he soon starts experiencing short-term memory loss and hallucinations while working on a particularly bizarre and seemingly unsolvable case. The other doctors suspect he's suffering side-effects from the drug they put him on, but he becomes convinced that he's actually still comatose. He resolves to break out of his coma by killing his own patient. {{spoiler|It turns out that he's right and it works, but there's a moment there where it looks like he was wrong and he's just murdered a man in a particularly gruesome way.}}
* In ''[[Community]]'' episode [[Community/Recap/S1/E19 Beginner Pottery|Beginner Pottery]] Jeff can't accept the fact he is unable to succeed in a pottery class, and ends us stalking and assaulting one of his fellow classmates.
** A more humorous version is [[Community/Recap/S2/E11 Abed's Uncontrollable Christmas|Abed's Uncontrollable Christmas]].
* Early on in ''[[Mouse (2021)|Mouse]]'', while in pursuit of a serial killer, Ba-reum receives a traumatic brain injury severe enough as to need surgery. Soon afterwards, disturbing things start happening that leave his sanity in question. Is he hallucinating due to an imperfect treatment or recovery? Did the villain sabotage the surgery somehow? Or did the events really occur but the villain is using a [[Cleanup Crew]] and other manipulations to gaslight him and those around into thinking he's just mentally ill?

== Music ==
* "The Ballad Of Dwight Fry" by [[Alice Cooper]].
** The theme of the later concept album ''From the Inside''.
* "My Mind Playin' Tricks On Me" by the Geto Boys.
* As the title suggests, the [[Coheed and Cambria]] album "Good Apollo, I'm Burning Star IV, vol. 1: From Fear, Through the Eyes of Madness" contains a lot of this. [[Mind Screw|Maybe]].
* [[Coldplay]] of all bands, did this in "A Rush of Blood to the Head".
* [[The Killers]] have their [[Murder Ballad|"Murder Trilogy."]] While the "Jenny Was A Friend Of Mine" and "Leave the Bourbon on the Shelf" don't qualify, "Midnight Show" fits pretty well.
{{quote|''The crashing tide can't hide a guilty girl
''With jealous hearts that start with gloss and curls.
''I took my baby's breath beneath the chandelier
''Of stars and atmosphere
''And watched her disappear
''Into the midnight show. }}
* The [["Weird Al" Yankovic]] songs "Albuquerque" and "Everything You Know is Wrong".
* The music video of "Asylum" by [[Disturbed]] has the patient/protagonist attempts throughout to escape from the titular asylum depicted this way. The events within are always surreal and usually overly violent and brutal (such as his being killed or beaten by the doctors and staff multiple times) while deranged and schizophrenic camera editing always follow the patient's POV (scenes without him are completely clean). The kicker is that after every one of his "deaths", [[Reset Button|he ends up back in his padded cell]], implying it was a delusion.{{spoiler|During the last event, thinking he'll just be sent back to his cell to tosses himself into a furnace to escape the doctors pursuing him. This one wasn't a delusion}}.
* The Violent Femmes' Country Death Song is sung from the point of view of a man slowly losing his mind, culminating in {{spoiler|pushing his daughter into a bottomless pit, and eventually hanging himself.}}
* [[Vocaloid|Megurine Luka]] as Sudou Kayo in [[Mothy]]'s [http://www.youtube.com/watch?v=m8L75guzMn4 The Tailor Shop on Enbizaka] is an [[Unreliable Narrator]] in this way. In the song, she tells the story in a way which leads the audience to believe that her lover has been cheating on her with three other women {{spoiler|who she ends up killing one after another}}. While her behavior alone makes her out to be pretty [[Yandere|crazy]], at the end of the song, it's revealed that {{spoiler|her supposed "lover" doesn't even ''know'' her, and the women she killed were his wife, sister, and daughter. When he fails to identify her, she kills him, too.}}

== Newspaper Comics ==
* ''[[Candorville]]'' generally implies either "everything supernatural is real" or "everything supernatural is a hallucination", but it keeps going back and forth on ''which'' it's implying. Saxon's crazy -- {{spoiler|he thinks he's a [[Dhampyr]]}}. No, wait, {{spoiler|he just showed off his [[Game Face]]}}. No, only Lemont saw it, and Lemont [[Weirdness Magnet|sees bizarre things all the time that nobody else ever sees]], so [[Unreliable Narrator|perhaps]] . . . Wait, Susan saw something too! But no, [[All Just a Dream|she was only dreaming]]. It seems the final conclusion will be {{spoiler|it's real -- Lemont's lawyer is shackled to a wall next to the skeleton of one of his friends, and his captor quite clearly has [[Fangs Are Evil|fangs]].}}

== Tabletop Games ==
* This is the main premise behind Evil Hat Productions' RPG ''[[Don't Rest Your Head]]'', where a low-level madness induced by chronic severe insomnia allows the characters to enter a ''[[Neverwhere]]/[[Dark City]]'' style [[Dark World]]. Depending on the GM, the setting can be treated as fully real, as existing only in the players' sleep-deprivation-addled heads, or as some [[Paranoia Fuel|combination of the two]].
* Similarly, there's ''[[JAGS Wonderland]]''. So you've started hallucinating and hearing voices—perhaps you're schizophrenic. No, wait, you're not schizophrenic—you've got this disease called Cyclic Psychoaffective Disorder. None of the medical professionals like to talk about it, because you can physically interact with the hallucinations... and it's contagious. No, wait, those aren't hallucinations—they're the things that operate on the lower levels of reality. You're not losing your grip on reality; ''reality'' is losing its grip on ''you''.
* In the [[Old World of Darkness]] Malkavian vampires are all like this. They definitely ''are'' vampires and they really ''do'' have a piece of a mad undead god in their minds, but other than that they shouldn't completely trust anything they see or hear.

== Theatre ==
* Shakespeare's ''[[Hamlet]]'' is perfect for this as the entire play is driven by Hamlet seeing a ghost of his dead father telling Hamlet that his uncle, the king's brother, is a murderer. The play then goes on to make Hamlet seem as insane as possible while still keeping everything the ghost said plausible, yet never confirmed.
** The guards see the ghost before Hamlet does. So unless they're not real either...
*** Woah woah woah. The guards definitely see ''something'', that's for certain. They believe it to be the ghost of Hamlet the elder. Notice that it never speaks to them and never confirms its existence to anyone but Hamlet. Hamlet goes out to meet the ghost alone, and only then does it speak. Indeed, later in the play the ghost appears to Hamlet while his mother is with him and only Hamlet can see the ghost. The only person in the play who has solid evidence that there is a ghost is Hamlet, and he very well could be mad as a hatter.
*** But Horatio, pretty much the sanest person in the play, is fully convinced it's the ghost of King Hamlet as well—it's only with his urging that Hamlet is even willing to show up. Basically, there's a reason ''Hamlet'' gets so many papers written about it.
*** It probably doesn't help that the oldest version we have of the story is from a time where, really, it was perfectly acceptable to believe in ghosts, and Hamlet (or, rather, the character Hamlet is an [[Expy]] of) was a fine cocktail of [[Obfuscating Stupidity|Obfuscating Mental Illness]] and [[Badass]] in a Viking shell, who survives his [[Roaring Rampage of Revenge]].
*** And of course, whether Hamlet really is mad or is just "putting an antic disposition on" has been the subject of massive debate for a couple hundred years. A convincing textual argument can really be made either way.
*** And it needn't be either/or either. Hamlet may have started off feigning insanity only for the same delusions to become real.
* A better example might be [[The Scottish Trope|the Scottish play]], where Banquo's ghost torments MacBeth. Some directors leave the ghost out of scene, leaving us to wonder whether the ghost exists or he's just going mad.
** As nobody else can see it when it is there, he probably is anyway. The hallucinatory dagger was probably the first sign.
** On the other hand, the man definitely ''does'' have witches screwing with his life. He can't have hallucinated them, since Banquo was there too.
*** It is entirely possible that the ''first'' time that Macbeth saw the witches they were real, and when he started his decent into madness, he hallucinates them, and everything else.
**** But then there are scenes with the witches where Macbeth isn't there, so that just screws everything up more. Those scenes may or may not have been written by Shakespeare himself.
* Some productions of ''Wozyeck'' designed the setting this way.

== Video Games ==
* ''[[Eternal Darkness]] -- Sanity's Requiem'' basically takes place in this trope. A lot of the creepiness comes from the fact that there ARE actually monsters, zombies and demons around... but is that sound of earth-shaking footsteps right behind you one of them, or just a sign that your reality-check has finally bounced? When a healing-spell misfires and blows off your torso, it could just be because the magic you use comes from an accursed tome of darkness, or it could just be a hallucination... also, the fact that most of the characters you play ends up going mad, dying, or both, helps to drive home the point.
** Of particular note is Dr. Maximilian Roivas. When playing as him, several of his servants suddenly attack him, and after killing them are revealed to have been possessed by Bonethieves. Listening to the comments of his Bonethief autopsies, as well as a later cutscene, strongly imply that not every servant killed had been the victim of a Bonethief...
*** [[It Got Worse|Oh, that chapter doesn't stop at implication]]. If Max talks to one of the female servants before he picks up the [[Tome of Eldritch Lore|Tome of Eternal Darkness]], she makes (relatively) normal conversation. After picking up the tome and incurring a bit of sanity loss, she giggles and tosses "something that looks like a human organ" into the cooking pot. However, if you kill her, you take a massive loss of Sanity, just as if you had killed someone innocent... and no Bonethief pops out of her.
* The ''[[Half-Life]]'' mod ''They Hunger'' played with this in the third chapter. The intro cutscene shows a hospital, with a doctor mentioning a delirious patient who keeps screaming about the living dead, as a baby from the maternity ward cries in the background. Then the game starts, and you jump out of your hospital bed and start killing the zombies who have taken over the hospital. But as you fight through the city, you keep hearing a baby crying...
* ''[[Silent Hill 3]]'' raises the possibility that it's an example of the trope, with a character first angrily decrying ("You come here and enjoy spilling their blood and listening to them cry out! You feel excited when you step on them, snuffing out their lives!"), then shockedly asking the game's protagonist, regarding the creatures she's fought and killed for the whole game, "Monsters? They looked like monsters to you?" He claims to have just been kidding... but he may have been just saying that to calm her down and the monsters were just her mysticism-addled visions of innocent bystanders... but then again, maybe he really was just kidding.
* ''[[Silent Hill 2]]''. {{spoiler|It's all in your head James}}. But if that's true, then why is it that {{spoiler|"You see it too? For me, it's always like this."}}
** Presumably, James has {{spoiler|entered Angela's 'Otherworld' when he sees the flames, just as he entered Eddie's when James fights him in the meat locker}}. Also, another case of this trope is the Abstract Daddy: a monster to us, but to Angela, it looks like {{spoiler|her father}}. And for that matter, {{spoiler|nobody ever sees Maria except James...}}
* ''[[Silent Hill: Shattered Memories]]'' may be a game about Harry trying to find his daughter Cheryl. Or maybe it's about {{spoiler|Cheryl finally giving up on her delusions of her father's ghost. But how does that explain Harry's conversations with Cybil? Or Michelle? Or Dahlia? Or any of the people he spoke to over the phone?}}
** It doesn't explain it. In fact {{spoiler|if you call the mall security, they mention that Harry ''can't'' be where he is, otherwise he would have tripped the alarms or shown up on the security cameras. Harry can't explain it either. This basically says that Cheryl's subconscious did create something. Maybe.}}
* ''[[Dark Corners of the Earth]]'' a game that comes complete with Sanity meter and hallucinations, is based on the works of [[H.P. Lovecraft]]. Thus, while it's easy to believe the events chronicled are real, the beginning {{spoiler|(which is also the ending, where the main character hangs himself in an insane asylum)}} coupled with repeated hallucinations of still being in the asylum during the game cause one to wonder if he is mad because of the events or the events came from his madness.
* Certain missions in ''[[Max Payne (series)|Max Payne]]'' are examples of this, as is the show-within-the-game ''Address Unknown''.
* The ''[[Darkseed]]'' duology, particlarly ''Darkseed 2''. The main character is undergoing therapy, and the psychiatrist just doesn't believe that the Dark World really exists. {{spoiler|Given the ending, whether Dark World exists really or is just a hallucination of Michael Dawson is an open question.}}
* The expansion pack ''[[Postal]] 2: Apocalypse Weekend'' plays with this trope. The game takes place after the Postal Dude has suffered a gunshot wound to the head at the end of ''Postal 2'', and as a result he often finds himself transported to a ''[[Silent Hill]]''-like "alternate reality" version of his current location, where the walls are made of blood and Gary Coleman-like demons appear and attack him. It's probably just a head-trauma-induced hallucination, though. Probably. Postal Dude even remarks "With my luck, that was probably really somebody's grandmother or something." after blowing away one of the demons with his firearms.
* ''[[Killer7]]''. You ''start out'' fighting alongside aspects of your [[Split Personality]], and still... [[It Got Worse|it gets weird]].
** Well, that's one interpretation. Of course, [[Suda 51]] himself [[Mind Screw|probably doesn't know what's actually going on]].
* The alternate ending to ''[[Scratches]]: Director's Cut'' has elements of this.
* ''[[Baldur's Gate]]'' nearly goes here. You're told, late in the game, that your foster-father, Gorion, was actually poisoned, not killed, and that the doppelgangers you've just been massacring ''really were'' the childhood friends they at first appeared to be. {{spoiler|Then the characters who told you this -- Elminster, Gorion and Tethoril -- turn out to be disguised doppelgangers, not themselves.}}
* The manual to ''[[American McGee's Alice]]'' has the case notes of Alice's psychiatrist, which match the [[Journey to the Center of the Mind|action in Wonderland]] very nicely. Is Wonderland some sort of objectively real dimension Alice is traveling in? Is it nothing but Alice's insanity? Is it somewhere in between and that nasty "psychiatrist" is helping crack poor Alice? You're never really sure, especially since the opening cinematic implied that the denizens of Wonderland woke Alice to save her life during a house fire.
** Taken [[Up to Eleven]] in the [[Alice: Madness Returns|Sequel]], when we actually see Alice blending wonderland and the real world. Maybe. It's not very clear... It's even been suggested that she was lobotomized halfway through the game and it was [[All Just a Dream]].
* ''[[Sanitarium]]''. [[The Reveal]] is sprung too early, but until then, it's not clear which parts are real, which parts are the main character's demented hallucinations and which parts may be someone else's deranged hallucinations.
* This trope is the main source of horror in ''[[Phantasmagoria 2]]: A Puzzle of Flesh''. The main character was recently released from a mental institution, and throughout the game sees and hears horrific things that no one else seems to notice.
* ''[[The Suffering]]'' is very much built around this torpe. On the one hand, there's definitely monsters tearin' shit up. On the other hand, the main character, Torque, is definitely out of his damn mind. On top of the constant hallucinations, he can transform in to [[Super-Powered Evil Side|a hideous monster]] that does excellent melee damage to foes, but suffers from health damage if used for too long. It's eventually revealed that Torque only ''imagines'' his transformation and the weird attacks he uses while in the form of the monster: it's all just him slaughtering people with his bare hands. This becomes very obvious when other characters react with surprise at how many enemies Torque killed while transformed, but never seem to notice any physical change.
* ''[[BioShock (series)|BioShock 2]]''. At the particular moment of the game, you got to {{spoiler|see the world through the eyes of a Little Sister}} for a while, which is true [[Cognitive Dissonance]].
* In ''[[Batman: Arkham Asylum]]'', you progress through multiple surreal segments in which {{spoiler|Batman is exposed to the Scarecrow's fear gas, and he is forced to witness his worst fears becoming real and to re-live the most horrifying and psychologically scarring moments of his life.}}
** The sequel, ''[[Batman: Arkham City]]'', also has a segment where Batman is given the "Blood of the Demon" from Ras Al Ghul and hallucinates surreal terrain and phantasmal enemies. In another he must shrug off the Mad Hatter's mind control in a battle that looks (to him) like it's taking place on the face of a giant watch floating in a bizarre environment. Batman also {{spoiler|spends a good chunk of the game slowly dying from blood poisoning}} and at one point is fighting Mr. Freeze and sees his face turn into that of the Joker.
* Not present in every story path, but definitely present in ''[[Tsukihime]]''. The entire story is told in the first person perspective of the protagonist, and due various drugs, [[Enemy Within|enemies within]], {{spoiler|a [[Psychic Link]] with the [[Big Bad]], who is an [[Ax Crazy]] [[Serial Killer]] vampire}}, and attempted [[Grand Theft Me]], Shiki's grip on sanity gets pretty strained at times.
* Some encounters with the Lovecraftian Old Gods in ''[[World of Warcraft]]'' including unsettling whispers directly to the player. A both very creepy and amusingly literal take on the "in the mouth of madness" phrase occurs if you die in the "brain" area of the fight with Yogg-Saron: your body appears in the middle of the boss itself, with your camera gazing out ''through'' its immense, gnashing teeth.
* ''[[Saya no Uta]]''... Through the eyes of Fuminori, whose senses had been inversed, every human being is as disgusting as a pile of organs and putrid flesh pouring pus. {{spoiler|The actual [[Eldritch Abomination]] looks like an angel to him.}}
** Not only humans, every single shape (His house, the sky, the cars) looks like is covered in guts and gore. Everything smells foul, sounds foul and feels foul to him.
** Then he finds some meat that smells nice...
* In the ''[[Dead Space (series)|Dead Space]]'' universe, there's quite a bit of this due to the influence of the mysterious Markers.
** In ''[[Dead Space (video game)|Dead Space]]'', Isaac goes aboard the Ishimura to find his girlfriend {{spoiler|who has been dead this entire time, and it was a combination of guilt, denial, and the Marker that made him believe her as still alive. [[The Mole]] reveals the truth to him before she's crushed into paste by the Hive Mind.}}
** In ''[[Dead Space 2]]'' {{spoiler|Isaac is fully aware that his mind can't be trusted and that Nicole is a hallucination, but he eventually begins to trust it which makes the vision's betrayal all the more awful at the end. Also, Stross is in the throes of this throughout the game.}}
** In ''[[Dead Space: Extraction]]'' {{spoiler|the first chapter is pretty much this, Sam Caldwell believes that dozens of maniacs are attacking him all the while being assaulted my mysterious symbols and the voices of his dead friends, but it turns out that he's just been shooting innocent people this entire time. He comes to this realization after being gunned down by the police.}}
* ''[[Alan Wake]]'' toys with this a few times, but ultimately, things reach the point where an actual malevolent supernatural force is the only reasonable explanation.
* ''[[Catherine]]'': {{spoiler|Catherine herself exists only to Vincent and the other men she is seducing (as versions of their ideal sex-pot); she's a succubus. This causes Vincent some grief towards the end of the game.}}

== Web Comics ==
* Under the influence of blue mushrooms, the cast of ''[[CRFH]]!!!'' have hallucinated multiple times, yet there's hints of truth slipping through the haze. In the most recent{{when}} case, they fully realized they were hallucinating and went with it anyway just in case they learned something important.

== Web Original ==
* From ''[[SCP Foundation]]'', the Keter-class [https://scp-wiki.wikidot.com/scp-870 SCP-870]. Here's the situation, you keep seeing this horrific, bestial monster that you are sure intends to kill you; you've seen it attack an unfortunate guy in the middle of a shopping mall, pouncing and swallowing him with one gulp. Everyone says you are nuts, doctors telling you you're schizophrenic and that it's via hallucinations. Well, [[Bad News in a Good Way|here's the good news]], they're wrong about the hallucinations, what you are seeing is real. Bad news is, you are indeed schizophrenic, as SCP-870 is a predatory abnormality that, for unknown reasons, can only be seen by someone with schizophrenia.

== Western Animation ==
* An [[Alternate Character Interpretation|alternate interpretation]] on ''[[Phineas and Ferb]]'' suggests the whole series is in Candace's deranged mind, paranoid about her brothers doing insane things.

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