History SanitySlippage / LiveActionTV

** Antagonist [[MagnificentBastard Dukat]]. He starts off as a scheming, megalomaniac, yet charming villain, gets gradually worse, especially in season six, until it all finally boils down to a psychotic MotiveRant that is declared in-universe to be a MoralEventHorizon: "I should've killed every last one of them! I should've turned their planet into a graveyard the likes of which the galaxy had never seen! I should've killed them all."
** Faked--''probably''--by Sisko in ''For the Uniform''. He even slips into the Joran [[TranquilFury voice]].

* ''Series/TheWalkingDead'': Several survivors of the ZombieApocalypse begin experiencing this from SurvivorGuilt or just the stress of dealing with the PrimalFear day in and day out.

** Frank Burns shows definite signs of slippage during the fourth and fifth seasons as Col Potter takes over the 4077th and he breaks up with Margaret Houlihan as she undegoes CharacterDevelopment. When Margaret announces her engagement to Donald Penobscot Burns has his first VillainousBreakdown and has to be talked down by his mother over the phone. While on leave Margaret and Penobscot got married, he has his second breakdown to Seoul. Apprehended by the military police, he is sent for psychiatric evalulation and transferred away from the 4077th.

* ''Series/{{MASH}}'': Although it's never shown onscreen, during the finale, after witnessing a traumatic event, Hawkeye begins to not-so-subtly show signs of a breakdown. Like being convinced one of the anesthesiologists was attempting to suffocate his patient with the gas mask, or crashing a jeep through the mess tent. Little indications of a stressful work environment.
** In "Bananas, Crackers and Nuts", Hawkeye fakes sanity slippage in order to weasel some R&R in Tokyo.
** This is also a subtle core theme for the show overall; the wisecracks and wacky antics are a lifeline of [[SafetyInIndifference detached]] GallowsHumor for a camp full of people each slowly being driven toward the DespairEventHorizon in their own way.

* The version of [[ComicBook/TheJoker the Joker]] in ''Series/{{Gotham}}'' has undergone several instances of sanity slippage, some caused by chemicals, some due to [[AmbiguousDisorder his worsening mental condition.]] [[spoiler: At the end of the fourth season, not long after he's introduced, he's sprayed by something called [[AppliedPhebotinum "insanity gas"]] by his identical twin brother, [[CaptainErsatz who was]] the show's [[DecompositeCharacter first take]] on the Joker. The insanity gas causes mad laughter like the Joker venom from the comics, but it also seems to make anyone exposed to it more aggressive than they were before. Before being exposed to the gas, he appears to be a harmless, if [[TheHermit reclusive]] and [[OmnidisciplinaryScientist brilliant engineer,]] but afterwards, he is a [[ColdHam cold-hearted]] {{manipulative bastard}} who [[LackOfEmpathy who lacks empathy]] to the extent that [[EvilCantComprehendGood he can't even understand]] why [[BatmanTheCharacter his friend, Bruce,]] no longer thinks of him as a friend after he becomes a terrorist. After he succeeds at his goal of cutting off Gotham from the outside world, but doesn't succeed in [[MindRape driving Bruce to the point where he is insane enough to team up with him]], he becomes [[StalkerWithoutACrush so desperate to maintain any kind of bond with Bruce]] that he comes up with an insane plan to put Bruce through even more terrible ordeals, just so they can be connected forever by hatred rather than friendship. He also begins to talk and giggle to himself during this period, [[SplitPersonality sometimes in the voice of his brother.]] Later in the season, he falls into a vat of his own chemical creation, which, like the insanity gas, also drives people insane, and he is severely burned by it. When he wakes up from the coma he went into after that incident, his sanity seems to have slipped even more; he admits that he only has some of his memories, and doesn't even identify with his own name and pre-Joker identity, anymore.]]

%%* ''Series/{{Oz}}'': Many a character undergoes this, especially Beecher in season 2 after taking a level in badass. He gets better.

** "Agent Obfusco" has Olive, of all people, having a meltdown over the eponymous agent becoming trapped in a portal of his own creation. To her merit, however, this occurs right after he tells her and Otto that they failed their test due to not completing it within an allotted time limit (which they had no idea of until he told them). Otto, naturally, helps her to get her sanity back in check so they can free Obfusco.
** The Season 2 episode "Olympia's Day" has perhaps the most realistic version of this trope in the entire show. Olympia's sanity continuously slips away over wanting to make every one of her co-workers happy by granting all sixteen of them access to a tiny interrogation room that was originally meant for her and the Noisemaker, and Ms. O showing her a huge stack of letters from people who ''don't even work at Odd Squad'' wanting the room sends her over the edge. It's only when she wakes up in Dr. O's office after blacking out that she admits to Ms. O her FatalFlaw: her inability to say "no".
** Oona is known as being CuteAndPsycho for being a little off her rocker at times and is easily the poster child for this trope when concerning this series. "The Cherry-on-Top-inator", however, shows just how psychotic she can get, from her bloodlust of smashing gadgets to pieces with her personal mallet to her dancing on the edge of sanity with each story she hears of how the titular gadget helped her co-workers. It makes one wonder if she would have gone after said co-workers with the mallet if the show weren't kid-friendly.

** Olympia gets another turn in "Other Olympia" when the Olympia from "Assistant's Creed" comes back with her partner, Ozric, after a year-long mission fighting a villain known as The Sandman and, upon meeting main-character Olympia, gives her the designation of "Other Olympia". Otis immediately knows that Olympia's sanity is going to topple just from looking at her [[TheUnSmile unnerving smile]], and he's right on the money -- her sanity does indeed begin to crumble the more she's referred to as "Other Olympia" (and even as "Other Other Olympia" at one point) and the more she has to clear up the name confusion with her co-workers. By the time she is denied cake from an agent's retirement party, she can't take it anymore and declares a "name-off" with the "Assistant's Creed" Olympia, where she ends up winning.
** "The Scientist" has yet another Oona-related example with her being trapped in an AlternateDimension where there are no other humans and where things are inverted, up to and including gadget numbers and functions. She ends up staying in the dimension for nearly ''half a year'', with only a video camera recording her day-to-day logs for whomever may find it in the future. While she initially enjoys being alone in the alternate-version Precinct 13579, she eventually gets bored and ends up talking to herself quite a lot, with the camera switching back and forth as though there are two Oona clones speaking to each other. Once she returns to the real world and excitedly tells Olympia and Otis about her experience, she comments that while she did battle a giant plant she inadvertently made grow to enormous proportions, [[EnemyWithout the real thing she battled was herself, and she won,]] implying that the "clone" she spoke to is possibly an inverted version of her.
** In "Who is Agent Otis?", Oona gets a rare subtle example, with her continuously offering Olympia beans when the two girls hide in what was formerly Oscar's bunker. As Olympia begins to leave to track down and confront Brad Hatter, the only villain left in town who wears a hat, Oona tells her that she must take some beans before she goes and comments about how it feels like they're crowding all around her. She's not wrong -- many unopened cans of beans litter the bunker and block a pathway -- but considering Oona doesn't really have her mental health in check, it can come off as her sanity teetering on the edge.

* ''Series/OddSquad'': This is a common odd medical condition known as "descending into mathness". It can involve those afflicted having vivid math-related hallucinations and can lead to {{Fainting}} in some instances, although the cause is generally unknown.

** Mike Nelson is probably one of the few hosts to suffer such moments a lot, though his slippage tends to lead to him crossdressing. In ''Film/TheCreepingTerror'', he believed himself to be Carol Channing and in ''Film/{{Laserblast}}'', he dresses up as [[Series/StarTrekVoyager Captain Janeway]].

** To [[TheSpock Spock,]] of all people, in "[[Recap/StarTrekS2E1AmokTime]]" when the [[MateOrDie Pon Farr]] Blood Fever hits him. He begins by just [[ForgetsToEat going off food]] and being a bit more reclusive than usual. He manages to hide his condition well enough that [[TheNotLoveInterest Kirk]] doesn't even realise there's anything wrong. Then he threatens to snap [[VitriolicBestBuds Dr Mc Coy's]] neck when the latter gets worried about him and tries to give him a medical checkup. He begins to lose his temper - quite violently, at times, alarming his crewmates. Then Jim finds out that Spock has been giving orders to redirect the ship to Vulcan, and doesn't even remember doing it. Things begin to go rapidly downhill from there, culminating in a DuelToTheDeath with Kirk where the stoic, pacifist, loyal Vulcan is reduced to the state of a wild animal, fully willing to murder his dearest friend. Fortunately, Kirk's apparent 'death' at his hands shocked him out of the Blood Fever, and by the end of the episode, he seems to be returning to normal (though not quite all the way there.)

** Specifically, [[spoiler:Will has extreme empathy that he uses to solve murders and encephalitis. Will's psychiatrist is a serial killer. Will's psychiatrist knows he has encephalitis, but as it worsens convinces Will that his hallucinations, sleepwalking, lost time and seizures have no physical cause. Will's psychiatrist encourages him to think that killing a different serial killer in the first episode [[EvilFeelsGood felt good]], manipulates him into shooting another serial killer while hallucinating the previous one, and frames him for multiple murders. Will actually copes remarkably well, given the circumstances.]]

** Cersei is much more calm, collected, and rational in the first season than she is in the second. Her loss of Jaime and Joffrey's increasingly out of control attitude, complemented by her father's suddenly dismissive attitude towards her don't seem to be doing well for her mental faculties. Her despair over her daughter Myrcella's impending ArrangedMarriage can't help, either. She comes within inches of poisoning Tommen during "[[Recap/GameOfThronesS2E9Blackwater Blackwater]]" when she thinks that Stannis is about to break down the door. In "[[Recap/GameOfThronesS1E5TheWolfAndTheLion The Wolf and the Lion]]", she's outright screaming with rage at Tyrion, as she believes he poisoned Joffrey, and by Season 5 she's noticeably resorting to alcohol continuously, further worsening her condition. By the end of Season 6, she's clearly gone off the deep end. She not only blows up the Sept of Baelor and dozens of nobles within, including her uncle Kevan and three of the four Tyrells, but she doesn't care at all that Tommen kills himself in the aftermath. She still believes she can create a great dynasty with her children dead and surrounded by enemies. In the Season 7 premiere, Jaime actually calls her out on this last point.

** The version of [[ComicBook/TheJoker the Joker]] in ''Series/{{Gotham}}'' has undergone several instances of sanity slippage, some caused by chemicals, some due to [[AmbiguousDisorder his worsening mental condition.]] [[spoiler: At the end of the fourth season, not long after he's introduced, he's sprayed by something called [[AppliedPhebotinum "insanity gas"]] by his identical twin brother, [[CaptainErsatz who was]] the show's [[DecompositeCharacter first take]] on the Joker. The insanity gas causes mad laughter like the Joker venom from the comics, but it also seems to make anyone exposed to it more aggressive than they were before. Before being exposed to the gas, he appears to be a harmless, if [[TheHermit reclusive]] and [[OmnidisciplinaryScientist brilliant engineer,]] but afterwards, he is a [[ColdHam cold-hearted]] {{manipulative bastard}} who [[LackOfEmpathy who lacks empathy]] to the extent that [[EvilCantComprehendGood he can't even understand]] why [[BatmanTheCharacter his friend, Bruce,]] no longer thinks of him as a friend after he becomes a terrorist. After he succeeds at his goal of cutting off Gotham from the outside world, but doesn't succeed in [[MindRape driving Bruce to the point where he is insane enough to team up with him]], he becomes [[StalkerWithoutACrush so desperate to maintain any kind of bond with Bruce]] that he comes up with an insane plan to put Bruce through even more terrible ordeals, just so they can be connected forever by hatred rather than friendship. He also begins to talk and giggle to himself during this period, [[SplitPersonality sometimes in the voice of his brother.]] Later in the season, he falls into a vat of his own chemical creation, which, like the insanity gas, also drives people insane, and he is severely burned by it. When he wakes up from the coma he went into after that incident, his sanity seems to have slipped even more; he admits that he only has some of his memories, and doesn't even identify with his own name and pre-Joker identity, anymore.]]

** Mike Nelson is probably one of the few hosts to suffer such moments a lot, though his slippage tends to lead to him crossdressing. In ''Film/TheCreepingTerror'', he believed himself to be Carol Channing and in ''Film/Laserblast'', he dresses up as [[Series/StarTrekVoyager Captain Janeway]].

* ''Series/{{Dexter}}'' wrestles with Sanity Slippage during the second season of the series.

** In "Bananas, Crackers and Nuts," Hawkeye fakes sanity slippage in order to weasel some R&R in Tokyo.

* ''Series/{{Oz}}'': Many a character undergoes this, especially Beecher in season 2 after taking a level in badass. He gets better.

*** Whatever [[spoiler:she]] did to [[spoiler:get out of the pocket dimension]] apparently pushed [[spoiler:Missy]] completely over the edge into a perpetually cheerful, self admitted "bananas" borderline {{cloudcuckoolander}}. who skips around, breaks into song apropos of nothing, and randomly switches between an English and Scottish accent. [[spoiler:She]]'s also the most sadistic and pointlessly cruel [[spoiler:incarnation]] yet. [[spoiler:Ironically, later on, she comes the closest any Master ever has to making a HeelFaceTurn.]]
** Hell, the Doctor himself gets this sometimes! The Eighth Doctor undergoes this twice, in [[spoiler:"Minuet in Hell" and "Zagreus"]]. The Tenth Doctor has one in [[Recap/DoctorWhoS30E16TheWatersOfMars "The Waters of Mars"]] that temporarily turns him into [[spoiler:[[AGodAmI the Time Lord Victorious]]]]. The final three episodes of Series 9 see the Doctor FreakOut and undergo a ProtagonistJourneyToVillain — becoming a WoobieDestroyerOfWorlds for a while — when he proves unable to handle his anguish and rage over [[spoiler:Clara's death]]. It's telling he needs [[spoiler:MindRape — delivered unto him by no less than Clara herself (though he does this voluntarily)]] to help him return to his best self in the end. The revival series has made it pretty clear that without companions to keep him grounded, the Doctor would likely undergo these slippages ''all the time''. Witness this exchange from "[[Recap/DoctorWho2006CSTheRunawayBride The Runaway Bride]]":

*** Whatever [[spoiler:she]] did to [[spoiler:get out of the pocket dimension]] apparently pushed [[spoiler:Missy]] completely over the edge into a perpetually cheerful, self admitted "bananas" borderline CloudCuckooLander, who skips around, breaks into song apropos of nothing, and randomly switches between an English and Scottish accent. [[spoiler:She]]'s also the most sadistic and pointlessly cruel [[spoiler:incarnation]] yet. [[spoiler:Ironically, later on, she comes the closest any Master ever has to making a HeelFaceTurn.]]
** Hell, the Doctor himself gets this sometimes! The Eighth Doctor undergoes this twice, in [[spoiler:"Minuet in Hell" and "Zagreus"]]. The Tenth Doctor has one in "[[Recap/DoctorWhoS30E16TheWatersOfMars The Waters of Mars]]" that temporarily turns him into [[spoiler:[[AGodAmI the Time Lord Victorious]]]]. The final three episodes of Series 9 see the Doctor FreakOut and undergo a ProtagonistJourneyToVillain — becoming a WoobieDestroyerOfWorlds for a while — when he proves unable to handle his anguish and rage over [[spoiler:Clara's death]]. It's telling he needs [[spoiler:MindRape — delivered unto him by no less than Clara herself (though he does this voluntarily)]] to help him return to his best self in the end. The revival series has made it pretty clear that without companions to keep him grounded, the Doctor would likely undergo these slippages ''all the time''. Witness this exchange from "[[Recap/DoctorWho2006CSTheRunawayBride The Runaway Bride]]":