Except for extreme cases such as [[TheSchizophreniaConspiracy paranoid schizophrenia]], or conditions with sympathetic social connotations (Down Syndrome; severe autism), there is a tendency in media to regard mental disorders as some kind of put-on or character flaw that is amusing at best and annoying at worst (not that the extreme illnesses are exactly treated like cancer-victims; in fact they can be treated ''worse'' than milder forms). The two most "comical" conditions are [[SuperOCD Obsessive-Compulsive Disorder]] and [[HollywoodTourettes Tourette's Syndrome]], both of which can be significant, sometimes disabling problems in real life.

At the very worst, a person is portrayed as being completely able to break out of their illness if they were to simply try hard enough -- in other words, they're just plain ''{{lazy|Bum}}'' in addition to the behavior itself. Depressive? Cheer up! Manic? Just take a deep breath and calm down. Obsessive-compulsive? Relax already. Delusional? Get a grip on that overactive imagination. An eating disorder? Please. You look fine! Hyperactive? Control yourself, my God. Paranoid? It's not all about you, you know! Anxiety with panic disorder? Suck it up, coward!

A genuinely ''good'' character will, however, treat the mentally disturbed with kindness and will nicely ask whether [[NoMedicationForMe they went off their meds]] and that's why they're acting up again.

This prejudice contributes to the mentally disturbed being {{Acceptable Target}}s for the most merciless cruel humor and parodization. This pertains to sociological stereotypes that most people will tend to [[UsefulNotes/VictimBlaming blame the victims of misfortunes]], in order to take credit for their own ''good'' fortune, rather than owning it up to plain luck of the draw (often because luck runs out, and this means that it's only a matter of time for them).

Note that this also pertains to the illusion of control that society presents regarding one's mental state, vs. one's physical state; i.e. few, if any, will blame victims of cancer (except for lung cancer), leukemia, or similar organic physical illnesses or injuries, telling the person to "toughen up" and "get over it", or otherwise calling them "weak" or "lazy."

See also: HollywoodPersonalityDisorders, InsaneEqualsViolent, FunnySchizophrenia, CategorismAsAPhobia, BlackAndWhiteInsanity, AcceptableTarget. If the exact nature of the disturbance isn't spelled out, it may be a case of AmbiguousDisorder.




[[folder: Anime & Manga]]
* ''Manga/SayonaraZetsubouSensei'' takes this one to its logical extreme. Half the cast, or more, suffers from some form of severe mental disorder, which is usually played for laughs (albeit intentionally dark and disturbing laughs).
* Alphonse and Edward from ''Manga/FullmetalAlchemist'' display all signs of PTSD when confronted with their old teacher, who was a firm believer in TrainingFromHell. Naturally, we're supposed to laugh. Meanwhile the trauma from the botched resurrection of their mother, which resulted in the loss of Al's entire body and two of Ed's limbs, is portrayed with the weight it deserves.
* Sakon Daimaru from ''Manga/{{Gamaran}}'' used to be sane, but became mentally disabled after the TrainingFromHell he suffered. Add his incredible martial arts to the lot and you get an HandicappedBadass and a ScreamingWarrior in battle.
* Yukishiro Enishi of ''Manga/RurouniKenshin'' is ''severely'' disturbed because he witnessed the death of his older sister Tomoe [[spoiler:at the hands of the protagonist Kenshin, who killed her by accident]] and the trauma is very apparent. His hair went [[LockedIntoStrangeness white]] soon after, he hallucinates seeing Tomoe, and if he tries to harm young women he becomes physically ill. To say nothing of [[AxCrazy his violent behavior]].
* ''Manga/MiraiNikki'' has Yuno Gasai. The series initially paints her as a typical {{Yandere}}, but slowly starts pulling the curtain away and revealing that her situation is ''much more complicated'' than it first seems: [[spoiler: she essentially has ''horrific'' PTSD from being tortured by her parents and then [[AccidentalMurder accidentally]] [[AllDeathsFinal permanently killing]] Yukki in the first run. Her actions are half from trauma and half from guilt, and when we're shown a Yuno with a much happier life in the Third World, she's ''much'' better adjusted.]]
* One could make a very good case for [[Anime/MobileSuitGundam Char Aznable]] qualifying as clinically insane during the events of ''Anime/MobileSuitGundamCharsCounterattack''. He's having constant flashbacks, he sees things and hears voices, and his cognitive dissonance has become so strong that he can somehow mentally reconcile dropping a meteor on the planet with his end game of "saving the world."
* ''Anime/MobileSuitGundamSEEDDestiny'' has Stella Loussier. Experimented on as a child, and subjected to massive quantities of mind-altering drugs, Stella is an IdiotSavant who can fly a HumongousMecha, but otherwise functions at the mental and emotional level of a five year old. Terrified of the world around her, she lashes out at anything that her superiors tell her is going to hurt her, burning down most of Berlin in a panicked effort to "make the scary things go away."
* Ken Kaneki from ''Manga/TokyoGhoul'' gains considerable mental problems after his torture at the hands of [[ThresholdGuardians Yamori]], with his hair turned white from the trauma. Though he pretends to have things under control, several of his friends recognize that he is slowly spiraling into madness and worry deeply for him. He's very clearly traumatized, mimicking the behavior of his tormentor and obsessed with becoming strong enough to protect everyone he cares about. When stressed, he suffers bouts of hallucinations or loses sight of himself to the extent he starts using [[UsefulNotes/JapanesePronouns different pronouns]] to refer to different pieces of himself. This ultimately comes to a head when [[spoiler: he gains his half-Kakuja form]], suffering from a complete psychotic breakdown and nearly killing his TrueCompanions in the process. It makes him realize how far gone he really is, forcing him to begin recognizing that his actions have been self-destructive. [[spoiler: He spends the final chapters of the series having another psychotic break, hallucinating for much of his battle with Arima and finally resolving that the only thing left for him to do is to [[UncertainDoom "rest and have a peaceful dream"]]. The sequel has left his ultimate fate ambiguous, thus far]].
** [[spoiler: He's still alive, though without his memories...and insanity. Even then, he loses control sometimes. Later on, he regains his memories and slaughters ghouls left and right.]]
* In the Monster Island arc of ''Manga/{{Cyborg 009}}'', one of the [[MadScientist scientists]] engineers insects that cause any people they sting to go insane. The victims seem to mentally regress to being infants, wandering around and needing others to feed and care for them. The cyborgs discover that scaring one of the victims sufficiently causes him to temporarily become sane, but he ends up reverting back after the shock wears off. While this is treated as a danger, the actual behavior of the victim the cyborgs find is PlayedForLaughs, with several joking about how 003 is being motherly towards him.

[[folder:Comic Books]]
* Most comic book villains are ''not'' this trope, with Arkham Asylum in particular standing as a tribute to the fact that most people do not understand insanity or the insanity defence.
* ComicBook/TheFlash villain Hunter Zolomon/Zoom is a legitimate example of a mentally disturbed individual. Traumatised by, among other things, discovering his father was a SerialKiller (whose last victim was his mother), being crippled in the same shootout that killed his father-in-law, and being crippled again by Gorilla Grodd a short time after learning to walk, Zoom believes that MiseryBuildsCharacter, and that he is helping the DC Universe's heroes by hurting them. Delusional, paranoid, holding a view of the world that is fundamentally at odds with reality, and verging on suicidal, Zoom is badly in need of institutionalization and therapy.
* ComicBook/TheFlash Rogue Heat Wave is a {{pyromaniac}} who burned down his childhood home and killed his parents in the process because he just couldn't help it. He's disturbed by his own insanity and has attempted therapy, albeit unsuccessfully.
* Franchise/{{Batman}} villain Killer Croc is another legitimate example. Having suffered massive amounts of abuse growing up and burdened with an increasingly monstrous set of deformities, Croc's mind was broken even ''before'' his condition started to eat away at his sentience. Nowadays his intelligence comes and goes DependingOnTheWriter. When it's gone he'll act more animal than man and it's an open question whether he can be held accountable for his actions.
* ComicBook/TwoFace may not have a real mental disorder, but there is no doubt that he is mentally ill. With a fractured psyche that leaves him totally dependent on coin tosses to make decisions, Two-Face is void of moral agency, and is one of the few patients at Arkham to actually belong there.
* [[ComicBook/AntMan Hank Pym]] is said to be bipolar in the short-lived ''ComicBook/AvengersAI'', and has had [[FreakOut numerous]] [[ThatManIsDead mental]] [[DrivenToSuicide breakdowns]] over the course of his history.
* DependingOnTheWriter, ComicBook/TheRiddler is sometimes depicted as this, with his fixation on riddles being an actual compulsion rather than a typical supervillain's focus on their gimmick. He's often ''tried'' to commit {{the Perfect Crime}} by not leaving behind clues, but always ends up doing so. One story even had him try to get around it by leaving riddles to other villains' plans, keeping his own a secret, only to unconsciously structure his riddles so that they formed one large riddle pointing to him when put together.
-->You don't understand... I really didn't want to leave you any clues. I really planned never to go back to Arkham Asylum. But I left you a clue anyway. So I... I have to go back there. Because I might need help. I... I might actually be crazy.

%%[[folder: Film]]
%%* ''Film/MrJones''.

* ''Literature/TheBelgariad'''s [[TheBrute Taur Urgas]], who in addition to being an AxeCrazy psychopath is also prone to fits in which he foams at the mouth, chews on furniture, and otherwise completely loses touch with reality. This is actually played for a degree of sympathy when Eriond notes that Taur Urgas' madness was so severe as to excuse him from responsibility for his crimes, something that the rest of the cast had not considered.
* ''Literature/TheElenium'':
** Adus is an illiterate, unwashed savage who acts as [[DragonInChief Martel]]'s [[TheBrute muscle]]. Barely capable of speech, and prone to eating raw meat, Adus is so dimwitted that the possibility of his being mentally handicapped becomes increasingly obvious. He's also prone to increasingly violent fits; by the end he's chopping his way through his own men to reach the heroes.
** Azash's worshipers tend to end up this way, especially once they lose their connection with him. The Lady Bellina, already cannibalistic and sadistic, completely loses her mind once her link to Azash is broken. Unable to speak or indeed, do anything beyond scream unintelligibly, she is confined to a tower in order to prevent her from harming herself or others.
* Christian Grey from ''Literature/FiftyShadesOfGrey'' has a number of psychological issues that he blames entirely on his dead mother (although she died when he was four and he was raised by a loving foster family after that), which include a violent personality, a desire to control everything in his life, freaking out when his chest is touched, hating blonde women (because he somehow was traumatized by a blonde policewoman carrying him away from his mother's body), and choosing young brunette women as submissives because they resemble his mother. These alternate between being treated by Ana as a series of endearing, if occasionally exasperating, quirks and being PlayedForDrama so Ana will treat him sympathetically. His therapist suggests to Ana that she's healing his issues simply with the {{power of love}}. Also, his love of BDSM and dislike of vanilla sex is treated as a symptom of how messed up he is.
* We are repeatedly informed that the Mad Wizard Antryg in ''Literature/TheWindroseChronicles'' is - well, mad - but it affects his behaviour so little that it manifests as peculiar dress sense and being a bit of a NightmareFetishist, or even pure ObfuscatingInsanity (a tactic he legitimately uses a lot). But this is more down to plot momentum and LawOfConservationOfDetail than anything, with the third book clearly establishing that even at his most lucid he has some delusional beliefs, such as a conviction that the secrets of creation are encoded in the shapes of tortoises' shells. His madness is said to be the result of serious emotional abuse he received as adopted son of the DarkLord coupled with years of confinement and punishment from the wizards, but it's also established he was slightly unhinged at the beginning - in fact, as a student of the DarkLord he'd tried to repress his own insanity to be better, and failed. By the time the books start he's well aware he's mad and [[TheMadHatter more than comfortable with that]], a state of mind he requires in order to function normally.
* In ''Literature/{{Impossible}}'', the curse on the Scarborough family causes any of them who fail to solve the impossible tasks before giving birth to be inflicted with some vague mental illness that causes them to wander aimlessly, be unable to properly communicate with others, and otherwise be incapable of caring for themselves. It's implied that the Scarborough women tended to be shunned in society for the shame of having insane mothers and Miranda's foster parents give up on her as a lost cause from the start, figuring that she'll just have whatever mental issues her own mother had. The fact that Lucy's foster parents ''aren't'' like this is pretty much the main reason she has a shot of beating the tasks herself - Soledad and Leo treat Miranda's insanity with sensitivity, hoping that professional help and modern medicine can help her. [[spoiler:While they do get her to a state-of-the-art mental clinic at one point, it's let unanswered if it would have helped. she's magically abducted away not long after.]]
* ''Literature/RabbleStarkey'': Mrs Bigelow has some kind of mental disability that prevents her from truly looking after her children. It is seen as problematic but something everyone can live with until Mrs Bigelow [[spoiler: nearly kills her four-year-old son by dunking his head underwater in a pond trying to baptize him]]. After that, she goes into a mental hospital where she stays for months.

[[folder: Live-Action TV]]
* ''Series/{{Scrubs}}'' usually plays right into this one for a cheap laugh but takes a long look at individual characters to find some genuine problems. This ranges from the psychologist's two o'clock client running into a shot just long enough to inform characters that "they've landed" to a surgeon unwilling to leave the operating room hours after performing surgery because he's still washing his hands.
** This latter scene developed into a serious, very well done, and poignant scene in which the main character sees just how much the surgeon with OCD actually suffers because of his condition, while prior to this it had been played mostly for laughs.
* As a kid watching ''Series/SesameStreet'', Forgetful Jones is quite funny. [[FridgeHorror But when you look back at it as an adult]], you are wondering what person thought it would be great to make fun of a man suffering from advanced dementia, who appears no longer be able to do anything unsupervised.
* In a throwaway joke in ''Series/{{Extras}}'', Andy balks at the prospect of being set up with a woman with bipolar disorder and says something like, "She'll forget to take her lithium [[InsaneEqualsViolent and kill me]]."
* In ''Series/{{Glee}}'', Emma Pilsbury's OCD is mostly shown as a strange character quirk instead of the debilitating mental illness that it is. The show also keeps making jokes about how Emma's OCD and germphobia has caused her to be a virgin at her age, as she can't make herself get intimate with people. It took until the end of season 2 for the show to actually treat her OCD seriously, by having her go to a therapist to get help, at which point she admits that she's actually ashamed of it and that it's basically destroying her life.
* In one episode of ''Series/{{CSI}}'', Grissom befriends the schizophrenic sister of the victim, who was driven insane by the same circumstances that led to the vic's death and is now a rambling bag lady. The end of the episode shows Gris walking next to the sister as she pushes her cart, having a lovely and surprisingly philosophical conversation with her regarding her delusions (she believes she's searching for something important, and when she finds it she can finally rest).
* Canadian television series ''Series/{{Cracked}}'' deals with a team of police officers and psychiatrists assembled to deal with crimes involving the mentally ill--whether as perpetrators, victims, or witnesses. Main character Aiden Black is himself suffering from symptoms of Post-Traumatic Stress Disorder and undiagnosed anxiety and mood disorders, stemming from his involvement in two fatal shootings, and as such has a great deal of sympathy for the victims of mental disorders. In the main, the show treats the mentally unwell as people, with a strong emphasis on treatment; one Season 1 episode, "No Traveller Returns", focuses on Aiden and resident psychiatrist Daniella Ridley having to make the case to a review board that [[ImAHumanitarian cannibal]], murderer, and paranoid schizophrenic Mandar Kush is fit for release from the mental ward he has been in for the past eleven years. They turn out to be entirely right--Kush has not had an episode in a decade, deeply regrets what he did, and is looking to make amends and reintegrate into society.
* ''Series/{{Justified}}'': Season 3 BigBad Robert Quarles spent his formative years being raped and abused by his heroin addict father's clients. As an adult he's deeply angry, prone to fits of irrational behaviour, dependent on pain-killers in order to remain mentally functional, and prone to reenacting the abuse he suffered, typically taking it out on male prostitutes. Damaged on a fundamental level, Quarles comes off as a very disturbed man trying to figure out why anybody would want to ''do this'' in the first place.
* Commonly, we're reminded in ''Series/DoctorWho'' that the Doctor is 'mad' or 'a madman' - particularly in the Creator/StevenMoffat era, which made the description of the Doctor as a 'madman in a box' one of its {{Catchphrase}}s. Like everything else about the Doctor, his actual mental health state is heavily [[EraSpecificPersonality Era Specific]], and the tone with which it's depicted goes up and down from kooky comedy-madman antics, to reasonably well-researched PTSD and/or depression, to ObfuscatingInsanity, to KnightTemplar BlackAndWhiteInsanity, to being a NightmareFetishist, to [[AGodAmI having a god complex]], to genuinely being unable to understand human faces, or to [[CloudCuckooLander just wearing silly clothes and making puns at the monsters]]. On top of this, a few of the actors playing the Doctor [[CreatorBreakdown had real-life mental health issues which they allowed to inflect their performances]], though this was likely for personal colour rather than an attempt to play the Doctor as actually being mentally ill.
** The Doctor's madness in the Moffat era arguably peaks at the end of Series 9. In the wake of a TraumaCongaLine that includes betrayal, capture and total isolation from anyone save the MonsterOfTheWeek, ColdBloodedTorture, '''and''' [[spoiler: Clara Oswald's unjust death]], the Twelfth Doctor suffers a severe SanitySlippage and in the SeasonFinale "Hell Bent" becomes obsessed with the TragicDream of [[spoiler: saving Clara from the grave]] despite the threat it poses to the continued existence of space and time. A key reason he pulls off the BatmanGambit required to attempt this is because '''none''' of the other characters recognize or care about what he's recently endured, and even criticize him for being angry enough about it to [[spoiler: overthrow and banish]] the people responsible for his suffering. After it becomes clear that he's gone insane, only one character ([[spoiler: Clara herself]]) recognizes the horrors of what was done to him and shows him real sympathy; in the end, returning to his best self requires him to undergo [[spoiler: Mind Rape of his memories of her]] to get rid of the anguish and rage that drove him to this point. ''Ouch.''

* ''Pinball/{{Metallica}}'' has Sparky, who's clearly insane, merrily strapped into an electric chair, and played entirely for laughs.
-->'''Sparky:''' “Hmmmm, smells like fried chicken!” \\
'''Robert Trujillo:''' “Smells like little crazy bastard to me.”

[[folder:Video Games]]
* ''VideoGame/FinalFantasyVII'' protagonist Cloud Strife suffers from bouts of delusions, hallucinations, remembering things that never happened to him, and subconsciously appropriating his friend Zack's life for his own. At one point he even has a [[HeroicBSOD spectacular mental breakdown]], ending up in a clinic. He eventually does come to terms with a lot of his problems after his friend Tifa takes a jaunt through his mind, and manages to be an effective hero nonetheless. Some have commented that the conceit of ''Film/FinalFantasyVIIAdventChildren'' - that Sephiroth will continue returning to fight Cloud for as long as Cloud lives, but that, with support from his friends, he can deal with it - works very nicely as a metaphor for recurring mental illness or depression.
* Despite being a survival horror game set in a mental hospital, ''VideoGame/TheEvilWithin'' has a suprisingly sympathetic portrayal in the form of Leslie Withers; he's clearly suffering from ''something'' severe enough that he can barely form a sentence or hold a thought, but he's certainly not violent or aggressive and tries desperately (as best he can) to warn you when something bad is about to happen.
* ''{{VideoGame/Hellblade}}'' protagonist Senua is a traumatized Celtic warrior who faces psychosis manifestations created by her own mind.
* ''VideoGame/KaneAndLynch'', of all things, got this one absolutely right. Lynch is a diagnosed schizophrenic with acute psychotic episodes. Where most media of the same caliber would be tempted to play this for laughs, Lynch is instead presented as a deeply troubled individual with enormous difficulties dealing with everyday life, and whose reactions to what he does during his episodes after they wear off are just as crippling as the episodes themselves.

[[folder: Webcomics]]
* In ''Webcomic/MareInternum'' Mike clearly has quite a few mental issues, some of which are probably from [[spoiler:being sexually abused by his uncle when he was a kid]] which eventually caused him to be fired from the Mars expedition, and the comic opens on him [[StartsWithASuicide trying to hang himself]]. It just gets worse from there.

[[folder: Web Original]]
* In ''WebVideo/TheLizzieBennetDiaries'', the trope is maybe criticized with Lizzie's views about Mrs. Bennet. Lizzie sees her as this, but everyone else insists that she is pleasant and kind, whatever annoying opinions and form of interest she takes in her daughters's current love life, which makes clear that Lizzie may be actually projecting her anxiety over her life on her mother, the only one to share it. The best example is the spinster/witch costume, leading to much AlternateCharacterInterpretation.
* On the humor website ''Website/SomethingAwful'', Asperger's Syndrome is apparently considered a great punchline, and this is starting to catch on in other places around the web. At least some of the humor is derived from the tendency of non-professional internet denizens to self-diagnose for the condition, as a way of stating that social ineptness is not their fault. Obviously, it takes more than just social ineptness to be diagnosed with Asperger's, but that doesn't stop the self-diagnosed from leaping to conclusions.
* In the Literature/WhateleyUniverse, there's a disease that some mutants have. Diedrick's Syndrome. It makes the sufferers sometimes break down into 'crazed supervillain' ranting and such. The best-known case at [[SuperheroSchool Whateley Academy]] is a popular target of the school bullies and elitists.
* Frequently averted and deconstructed on ''Website/{{Cracked}}'' which has many articles that point out how reductive a viewpoint this is, and how it completely ignores genuine mental anguish that needs to be addressed. In particular John Cheese, who himself suffers from Depression, seems to be angered by it and wrote that [[HeartwarmingMoments going to see a counselor or feeling depressed doesn't make you crazy, and urged young people to seek help if they're going through a crisis]].
** The aversion is more notable considering it's a comedy site. However this is not to say, there aren't jokes in their articles about mental illness. Just that they treat mental illness as a serious condition. This aversion is justified because a lot of the articles about neurological disorders are either written by people who have them or people who have interviewed mentally ill persons beforehand.

[[folder: Western Animation]]
* Ren from ''WesternAnimation/TheRenAndStimpyShow'' is probably the most famous example from Western animation. However, unlike most examples, his psychotic freak-outs weren't always played for laughter. While he did display InsaneEqualsViolent behavior, it was always when he was being ''normal''; when his manic side was triggered, that's when he snapped into batshit terrifying, yet non-violent mode. Examples include "Stimpy's Fan Club", in which a quite long and elaborate scene is dedicated to him considering killing Stimpy (complete with rambling that "his hands are dirty, the dirt won't come off" and that "with these hands, he holds the fate of millions"), but he doesn't lay a finger on him throughout all of it. There's also "Sven Hoek", in which he becomes furious with his cousin Sven and Stimpy, leading to another disturbing monologue. It truly gives a twist to Ren's personality, at least before he was [[{{Flanderization}} flanderized]] post-season 2.
* Taken UpToEleven in ''WesternAnimation/{{Kaeloo}}'', where one episode showed the entire cast to be in need of intensive psychotherapy.
* In ''WesternAnimation/MyLittlePonyFriendshipIsMagic'', "Screwy", a clearly insane patient in the Ponyville Hospital's mental ward, is literally barking mad. Fortunately, in a later episode, she has a cameo that shows she's recovering, now living in a regular house with a nurse to look after her.
* On ''WesternAnimation/TotalDramaRevengeOfTheIsland,'' Mike has "[[SplitPersonality multiple personality disorder]]" that is pretty much PlayedForLaughs and a LovesMyAlterEgo-styled LoveTriangle involving Anne Maria and Zoey. It takes a much more central role in ''All Stars'', where [[spoiler:a new personality is revealed, who takes over Mike's body completely and becomes the BigBad.]]
* In ''WesternAnimation/AdventureTime'', the Ice King suffers from an Alzheimer's-like dementia and hallucinations; while he's usually PlayedForLaughs, ([[CerebusRetcon especially in the beginning]]) he has some truly heartbreaking moments. The Ice King's condition [[spoiler:is due entirely to his magic crown messing with his mind. His 'hallucinations' are also implied to be him actually seeing into other dimensions due to the crown. In one episode his sanity was ''immediately'' restored when the crown was temporarily depowered.]]
** The Royal Tart Toter and Lemongrab, as well. Tart Toter is senile and schizophrenic, and Lemongrab was [[WordOfGod intentionally]] to come across as [[AmbiguousDisorder (among many other things)]] severely autistic.
* The Trickster is implied to be this in the ''WesternAnimation/JusticeLeagueUnlimited'' episode "Flash and Substance". The Flash ([[FriendlyEnemy with whom he's good friends]]) lightly admonishes him for [[NoMedicationForMe not taking his medicine]], he's genuinely surprised when he's pointed out he's in his supervillain suit, and he agrees to give information on other villains in exchange for Flash visiting him in the hospital to play darts. The soft kind.

[[folder: Real Life]]
* Samuel Cartwright identified [[http://en.wikipedia.org/wiki/Drapetomania drapetomania]], a common mental illness among 19th century American slaves that irrationally compelled them to run away from their owners. He recommended treatment by flogging. It should be noted that this idea was widely mocked even at the time; Cartwright's contemporaries noted that, as European indentured servants would also run away, clearly the disease was European in origin and had been introduced to Africa by slave traders.
* In the Soviet Union, being a dissident was considered a sign of mental illness, as well -- and was used as a thin veil for torture in mental hospitals, disguised as "treatment."
** And not only in the Soviet Union; Hitler's first euthanasia victims were 28 mental patients, while the United States likewise sometimes classified non-conformity to various legal requirements as mental illness-- and subjected victims to similar treatments, despite later being proven wrong.
** Oppositional Defiant Disorder is a real diagnosis that is often misapplied to any child with behavioral problems, just like ADD is often misapplied to any child who gets bad grades.
* Any term used to describe the mentally handicapped gets used as an insult. Retard is merely the best known in a long line of these - moron was once a medical term. People, mostly on the internet, often use autistic as a synonym for social ineptitude, or say someone has ADD when they have trouble focusing. This process is known as the euphemism treadmill, and is inevitable, due to human love of simile, metaphor, hyperbole, and insult.