->''"Like many games with a [[HPLovecraft Lovecraftian]] bent, [[VideoGame/AmnesiaTheDarkDescent it]] implements a [[InvokedTrope sanity meter]], as though sanity is like diesel oil or something, and you can get a reading on it by sticking a dipstick in your ear."''
-->-- '''[[WebAnimation/ZeroPunctuation Ben "Yahtzee" Croshaw]]''', [[http://www.escapistmagazine.com/videos/view/zero-punctuation/2092-Amnesia-The-Dark-Descent Amnesia: The Dark Descent review.]]

Some games will try to measure [[KarmaMeter how bad or good you're being]], on the basis that the game is set in a moral universe. [[WellThisIsNotThatTrope This ain't one of those games.]] ''[[CosmicHorrorStory This]]'' is one of those games where [[RealityIsOutToLunch the very nature of reality is mutable]], there are ''[[EldritchAbomination things]]'' out there beyond human imagining that mean us ill, and [[MindRape you've encountered several of them first hand]]. After a while, that's ''really'' going to wear on a person...

The Sanity Meter measures how well you've managed to keep your mind together when facing the horrors from beyond reality's edge. Some games will actually merge the Sanity Meter and the KarmaMeter, on the grounds that [[VideoGameCrueltyPunishment doing enough horrible things may either give you Post Traumatic Stress Disorder or disconnect you from the activity altogether]]. Either way, you'd better keep all your marbles clutched tight, 'cause it looks like Cthulhu's coming around again.

Compare MoraleMechanic.

"Sanity Meter in video games causing various {{Interface Screw}}s on decrease" is, [[DisneyOwnsThisTrope by the way]], [[http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=6935954 patented]] by Creator/{{Nintendo}}, the publishers of ''VideoGame/EternalDarkness''.

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!!Examples of this trope include:

[[foldercontrol]]

[[folder:Anime and Manga]]
* ''[[LightNovel/HaiyoreNyarkoSan Nyarko-san]]'', being one big love-letter to the CthulhuMythos, references SAN points pretty often. Such as when Mahiro sees Nyarko [[OverdrawnAtTheBloodBank brutally slaughter a nightgaunt]].
-->'''Mahiro:''' [[MadnessMantra It's just ink it's just ink it's just ink...]]
** In fact, the opening theme for the 2013 series is underscored by a repeated chant of "SAN-chi, pinchi!" which means "Your SAN points are in danger!"
[[/folder]]

[[folder:{{Literature}}]]
* Creator/UrsulaKLeGuin's short story ''SQ'' is a fable about the development of a scientific, accurate method of measuring a person's sanity (the Sanity Quotient score) and the unfortunate effects it has on society.
[[/folder]]

[[folder: Tabletop Games]]
* ''TabletopGame/CallOfCthulhu'' pretty much [[TropeMaker pioneered]] the Sanity Meter. Each character starts with some measure of Sanity out of 100. When encountering a Mythos horror, or something just plain horrific, they roll their Sanity score. If they succeed, they roll to see how many of a smaller amount of Sanity points they lose; if they fail, they roll to see how many of a ''larger'' amount of Sanity points they lose (e.g., "roll for 1d6/1d20 SAN"). SAN points can be regained through psychotherapy and successful adventuring, but learning more about the Mythos ''permanently'' decreases your maximum Sanity. In fact, it is absolutely impossible to learn everything about the mythos without your SAN falling to 0 before.
** A form of Sanity Meter is actually implemented in the FirstPersonShooter ''VideoGame/CallOfCthulhuDarkCornersOfTheEarth'', where the longer you spend looking at (or just being around) the horror scenes, the more disturbed the protagonist becomes, eventually bringing in InterfaceScrew and, at one point, suicide.
** In another take on Lovecraft [=RPGs=], Trail Of Cthulhu, the Sanity Meter is broken down into two parts: Stability and Sanity. The former represents short-term sanity and explains how you can have characters who are nuttier than a bag of fruitcakes and yet still interact with society on a relatively normal level. Stability can regenerate, but once a character loses Sanity points, they're generally not getting them back.
** Parodied in ''TabletopGame/{{Toon}}''. One of the settings in the ''Tooniversal Tour Guide'' supplement is "[[ParodyNames Crawl of Catchooloo]]", where exposure to the eldritch but otherwise strait-laced minions of the Elderly Gods drives the 'toon [=PCs=] ''sane'' (since they're already crazy to begin with). Sane [=PCs=] become boring, unremarkable characters with pointlessly dull interests.
** ''TabletopGame/ArkhamHorror'', being CthulhuMythos TheBoardGame, also makes use of sanity rules. Seeing monsters and casting spells are the primary cause of sanity loss, but many encounters can also trigger it. Being reduced to zero sends you to Arkham Asylum ([[VideoGame/BatmanArkhamAsylum not that one]]) with some items lost. (Before long, you'll regain enough Sanity to leave ... but you'll be back. Oh yes. This game takes ''hours.'')
* ''[[TabletopGame/ChangelingTheLost Changeling: the Lost]]'' has a Clarity rating for its characters. Unlike the standard [[KarmaMeter Karma Meters]] for the other World of Darkness games, Clarity is more a rating of how well a person's able to hold it together after being put through hell at the hands of TheFairFolk. Murder and theft count as sins, but so do taking psychotropic drugs and experiencing unexpected life changes.
** There is also the fact that in all of the gamelines, when the KarmaMeter decreases, a charecter has to roll to determine if they gain a Derangement. The Storyteller is advised to select a Derangement appropriate to whatever caused the KarmaMeter to decrease.
** The [[KarmaMeter Morality]] system has now been readjusted with the upcoming God-Machine Chronicle so that vanilla mortals now have Integrity instead. It doesn't so much measure general levels of moral degradation as it does one's ability to deal with the horrors of the world.
* ''TabletopGame/{{Exalted}}'' has the Limit meter, which measures mental and emotional stress. Max it out, and it drops back down to zero...because you've just unleashed all that stress in an outburst of insanity that can last anywhere from a few hours to ''several months.''
** The Chimera rules in the Lunars book also work like this, only fused with a sort of mutation meter: if you undergo this break in the Wyld, and you're a Lunar without moonsilver tattoos, you gain a permanent point of Limit. By about five or six, Lunars with tattoos will try to kill you on sight. When it hits ten, your mind and body are both reduced to screaming madness.
* Palladium's RPG system has a [[http://www.mymegaverse.org/Games/Mechanics/Palladium/House/hf.shtm horror factor]] stat for how monsters affect your sanity, simply by looking at them.
* The ''TabletopGame/DungeonsAndDragons'' setting ''TabletopGame/{{Ravenloft}}'', based on Victorian horror, adds to the traditional saving throws of Fortitude, Reflex, and Will by adding saving throws for Fear, Horror, and Madness.
** In second edition, when Ravenloft first became a full-fledged campaign setting, Fear, Horror, and Madness were added to the ''five'' saving throw categories. In third, they became extensions of Will saves.
* The Madness Meters in ''TabletopGame/UnknownArmies''. There are five; Isolation, Helplessness, Violence, Self, and The Unnatural. Depending on how well you roll when confronted with triggers, you either fill them with a Failed notch, or a Hardened notch. The more Failed notches you gather, the more likely you are to break down crying when you experience a trigger; the more Hardened notches you gather, the more immune you become to the trigger (to the point where a character with all Hardened notches in their Violence meter becomes a sociopath who doesn't really see the problem with carving a guy's face off with a potato peeler, and is only vaguely aware that others might not feel like he does).
* ''[[TabletopGame/VampireTheMasquerade Vampire: The Masquerade]]'' has a Humanity meter for vampires; the lower it becomes, the greater the chance that a character will Frenzy, causing them to lose all control and attack targets randomly (both enemy and friendly targets) until it fades away.
** A character's Humanity stat in the table game did much more than it did in Bloodlines. The Humanity stat for vampires is curious in that it did double duty as Sanity Meter and KarmaMeter, but does not stop you from picking up mental illnesses for other reasons. The Humanity Meter indicates what sort of wrong doing bothers a particular character, where a saintly person might feel guilty for selfish thoughts, most humans draw the line at theft, and a person low on the meter might be bothered by "Acts of Casual Perversion" or however it was phrased. Humanity kept the character from giving in to the monstrous barbarism ("Beast") of their undead state, but it didn't protect them from suffering OCD, schizophrenia, or other forms of mental illness. You could be a paranoid schizophrenic saint who had their "Beast" on quite a leash - as a starting character.
** Low humanity vampires also found it excruciating to act in the day, had extreme difficulty in mimicking human physiology when it would help them (for example, warming your skin so a potential meal you were attempting to seduce wouldn't realize you were a corpse), and at Humanity Zero, a character would pretty much become a mad dog who had to be put down. Many princes of the Camarilla (the "less evil" faction) would put a vampire down before Humanity 0 just because they became so violent, inhuman, and AxeCrazy they would threaten TheMasquerade just by existing.
** The game also featured alternative moral systems which were horrifying and outright evil by pretty much anyone's standards, but kept the Beast at bay. Such characters dove headfirst into being monsters to avoid becoming berserk, mad killing machines. For examples, one path says [[http://wiki.white-wolf.com/worldofdarkness/index.php?title=Path_of_Night be God's personal scourge]], another mandates you should [[http://wiki.white-wolf.com/worldofdarkness/index.php?title=Path_of_Power_and_the_Inner_Voice be a ruthless bastard]] with ChronicBackstabbingDisorder, and a third suggests you become an [[http://wiki.white-wolf.com/worldofdarkness/index.php?title=Path_of_Bones emotionless killer and student of death]]. Characters on these paths used very dark BlueAndOrangeMorality to remain less insane than the beast.
** ''Vampire: The Dark Ages'' featured alternate paths than Humanity which would be similar to Humanity and served a similar purpose. For example, the [[http://whitewolf.wikia.com/wiki/Road_of_Heaven Road of Heaven]] put religious duties first, human ethics second, but the overlap between them was very high. Such a character fought the Beast with their faith.
* ''TabletopGame/WarhammerFantasyRoleplay'' and ''TabletopGame/DarkHeresy'' both have Insanity Points, which measure just how unhinged you've gotten by your adventuring. Encountering a sanity-blasting scene makes you test your willpower, with failure leading to one or more automatic insanity points.
** In ''TabletopGame/WarhammerFantasyRoleplay'' you need to make a willpower roll for every Insanity Point you gain above 5; failure on this roll or reaching 12 insanity points resets your points to 0 and gives you a major derangement that will cripple or render your character unplayable right off the bat. On average, a bad roller will get two-three insanity points per session; double that estimate for a magic user. Unless you have a Gold Wizard, a very lucky brain surgeon or a Priest of Shalliya amongst your list of friends, insanities and insanity points are incurable.
** ''TabletopGame/DarkHeresy'' has a 0-100 score on insanities: You automatically start getting some minor derangements once you get over 30, with the number and severity increasing for every 10 over that. Once you reach 100, your character is unplayable. Unlike in ''WFRP'' insanity can actually be a ''good'' thing as it makes you more resistant to fear: A character with more than 80 insanity points can stare down an EldritchAbomination without much trouble, but at that point the voices in his head will already be doing far worse to him on a daily basis. On average, a session of Dark Heresy is about six-eight insanity points for an unlucky roller, with about two-three more per session for being or standing too close to a psyker. Insanity points can be bought off during reconciliation time for about 100 XP a point.
** Other games in the 40K RPG line handle insanity as well as [[TheCorruption Corruption Points]] in different ways. ''TabletopGame/{{Deathwatch}}'' Space Marines who gain too much Insanity suffer from varying levels of the "Primarch's Curse", which is dependent on their chapter; they're immune to effects from Corruption (which tends to lead to madness and mutation) unless they hit 100 points at which point they're removed from play permanently. ''TabletopGame/BlackCrusade'' characters are nearly immune to Insanity, since they serve the [[EldritchAbomination Gods of Chaos]] - they are considered to have already reached the end of the 100 point score of the other games and [[CrazySane come around again]]. ''TabletopGame/OnlyWar'' and ''TabletopGame/RogueTrader'' treat it similarly to Dark Heresy, although Rogue Trader expansions ''Into the Storm'' and ''The Soul Reaver'' gives options for certain Xenos characters. Both the Orks and Dark Eldar are effectively immune to insanity, not because of innate wholesomeness but because they're already [[BlueAndOrangeMorality inherently insane by human standards]], and there's no functional difference between "Normal Ork" and "Extra Crazy Ork".
* The attempt to make a ''[[Literature/TheWheelOfTime Wheel of Time]]'' RPG based on 3rd Edition TabletopGame/DungeonsAndDragons rules had this for male channeler characters. As male channelers eventually go insane, each time the character gains a level or uses too much power, he has to roll a die to determine how much sanity he loses. There was also a table laying out what psychoses the characters should manifest at what levels of sanity.
* While TabletopGame/{{GURPS}} doesn't have a sanity meter in the basic game (though it's very easy to add one, considering the system), it does include Fear checks whenever a PC encounters something particularly or personally terrifying. The basic game includes a massive table of effects that can be caused by fear, from becoming somewhat shaky to falling into a coma.
** GURPS Horror (for the system's 4th Edition) adds rules for Stress, Derangement, and Insanity.
* ''TabletopGame/DontRestYourHead'' possesses a Madness pool of dices. Usually up to 6 can be used at any time (and they are required to use the [[PowerBornOfMadness Madness Talents]]); the more are used, the more likely you are to spend a "fight" or a "flight" reaction. If none of these are available, the character ''snaps''. When it comes to its senses, the reactions are back, but one Discipline dice gets replaced by a Madness dice. Which allows more powerful uses of one's powers, but also makes it more likely to snap again. And if all Discipline gets consumed, [[AndThenJohnWasAZombie well...]]
[[/folder]]

[[folder: Board Games]]
* House on Haunted Hill features sanity as one of your stats. Like all of the other stats, it is used for various challenges, and if it falls to 0 your character dies.
* Fantasy Flight Games' Arkham Horror and Mansions of Madness both feature a sanity stat, naturally, since they are both Call of Cthulhu licenses. Encounters with monsters and mythos horrors can lower the characters' sanity. Strangely enough though, being reduced to 0 sanity is not terminal in either game, being mostly a speedbump in the former, and increasing the chance of your character doing horrible crazy things in the latter.
[[/folder]]

[[folder: Video Games]]
* Alice from ''[[VideoGame/AmericanMcGeesAlice American McGee's Alice]]'' has two meters. Her Strength of Will is how much ass-kicking she can deliver while her Level of Sanity is how much more ass-kicking she can receive. She gets more sanity by drinking the life essence of creatures she's killed. Riiiight. Of course, when you're basically wandering around in your own head, and the creatures you're killing are literally your own inner demons made manifest, it makes a certain amount of sense that taking them down would improve your sanity. (Okay, yeah, it's technically a Health Meter in all but name. WordOfGod said that plot-wise, this was just a [[RuleOfCool more interesting]] way for Alice to restore lost health than finding bandanges or medicine lying around Wonderland like it's often done in games like this.)
* ''VideoGame/AmnesiaTheDarkDescent'' has one of these, in much the same vein as Call of Cthulhu. It drains whenever you either look directly at a monster, linger in the dark, or encounter something horrific. Regarding the InterfaceScrew, it can range from a drunken haze to laying down and dragging yourself along while insects crawl along your field of vision, and paintings become grotesque. Once it's low enough, the monsters will chase after you.
* ''VideoGame/ClockTower'' 3 has a panic meter. If it fills, Alyssa starts running around uncontrollably. Cue "[[Series/TheBennyHillShow Yakety Sax]]".
** ''VideoGame/HauntingGround'' has a very similar concept. If Fiona reaches "panic mode", she becomes disoriented and cannot be well controlled by the player (to the point where the entire screen goes monochrome and disables use of the inventory/item menu).
** ''Clock Tower: The First Fear'' has this too, but it is slightly different in that it simply causes you to trip more frequently and makes traps more likely to kill you.
* ''VideoGame/{{Elona}}'' has a sanity stat. It is, however, mistranslated and actually a measure of insanity, as the healthiest possible level is 0. As it increases you are more vulnerable to effects that cause the insanity status which causes you to lose control of your character.
** Given the happenings of Elona [[FanWank fan theory suggests that this is an accurate translation, everyone in Elona is already insane,]] and that sanity only causes repeated suicide attempts, hence the random poisoning, bleeding, dizziness, and nausea that sanity brings.
* ''VideoGame/EternalDarkness'' popularized the Sanity Meter in video games. If it starts going low enough, you experience hallucinations; if it drains entirely, you take damage whenever a monster sees you. These hallucinations include BreakingTheFourthWall, reciting Hamlet, healing spells that backfire and cut you in half, and most interestingly, {{Interface Screw}}s such as game resets, cranking down the volume, switching to another video input, or "deleting" your savegames instead of saving.
* ''VideoGame/{{Fahrenheit}}'' has a Sanity Meter for each primary character. It's more about emotional stability than actual sanity, however; once it reaches zero, the character experiences a complete mental breakdown, and it's game over. It also functions comparably to a KarmaMeter: carrying out morally suspect actions will cause it to drop, and vice versa.
** Tyler gets one moment at the end of the game, [[spoiler: where he has to choose between his duty to the NYPD, or his long-time girlfriend that he loves who is leaving the rapidly freezing north for Florida. Interestingly, regardless of which choice you take, his sanity meter gets dinged (taking about a 50% loss if he leaves, and a whopping 95% crash if he stays). In both cases, it's entirely irrelevant, however: he's never seen again.]]
* The Nightmares quality in ''VideoGame/FallenLondon'' is an inverted sanity meter - it starts at zero, and increases as you go through particularly horrific experiences. At eight you GoMadFromTheRevelation. It can be brought back down through particularly soothing experiences, writing down some of your darker secrets in journals, [[SocializationBonus telling a friend about your fears]] (which increases ''their'' Nightmares slightly), or [[BrainBleach laudanum abuse]]. Once you GoMadFromTheRevelation, it can be easily brought back down through actions in the special location you're sent to, but once you become sane again, you will ''lose most of your dream progress'', making it the most punishing of the four Menace locations. And considering that you access one of the other Menace locations by ''[[DeathIsCheap dying]]'', it seems that going insane is a FateWorseThanDeath.
* For an incredibly early (perhaps the earliest?) example, check out Domark's 1985 ''Videogame/FridayThe13thTheComputerGame'' on the Commodore 64, Amstrad and Spectrum (it's nothing like [[{{VideoGame/Friday the 13th}} the NES version]]). The game has a sanity/fear meter that raises as the game goes on. It's represented as a kid's head, with the hair starting to stand on end as you get more frightened. If the meter maxes out, you die of fright... this almost never happens in-game, but it does increase the chances of seeing hallucinations (a pile of skulls covered in blood, someone with a machete through their head, etc) accompanied by a blood-curdling scream. Surprisingly effective for 16-colour graphics!
* The ''{{Geneforge}}'' series has a very simple (and invisible) one. It increases every time the PC uses a canister. Use too many and people will start to notice it and react to the PC differently. The PC will also occasionally go into an uncontrollable rage and attack people.
* ''{{Lusternia}}'' has one, which is gradually eroded by spending time on [[DeathWorld The Astral Plane]] or [[WombLevel inside]] [[CosmicHorror Muud]]. It causes the player to hallucinate, and [[ScrappyMechanic cancels a lot of the commands you enter]].
* The ''ShadowHearts'' series has Sanity Points (SP), which deplete by 1 with each combat round. Once it hits zero, the character goes Berserk, attacking randomly without player input; if they end a battle in Berserk status, they can't remember the events of it and thus gain no experience points. Harmonixers lose Sanity Points faster when they use their Fusion abilities (demons and/or spirits attack their sanity), but they ''start'' with about twice the SP of any other character. [[spoiler:Except Johnny Garland, because he never had the training to handle it.]]
* ''VideoGame/TheThing'' gives your party members sanity meters. If a Thing tries to eat them, they won't react well. (Not uncommonly, one of ''them'' is a thing, and the others utterly freak out when they're betrayed.)
* [[spoiler: Akiha's]] hair in ''{{Tsukihime}}'' is actually a sanity meter of sorts. The redder it gets, the closer she is to falling into madness from drawing too much upon her demonic powers. It's not actually until [[RedEyesTakeWarning her eyes turn red]] that she loses it, however. [[spoiler: Normally, she should have had the strength to better resist that, but she's giving half of her life-force away to Shiki. On another note, the one time she actually does go insane, it's possibly the result of a partial possession by a mad ghost whom she accidentally "ate".]]
* The battle with [[EldritchAbomination Yogg-Saron]] from ''{{World of Warcraft}}'' uses a sanity meter. Players start with 100, and Yogg has numerous abilities that reduce it. The only way to recover sanity is to stand in one of the green beams of light (sanity wells) situated around the room. If a player reaches 0 sanity, they go insane and begin to attack all the other players in the room until they are killed (the player will actually start seeing all his fellow players as Faceless Ones, servants of Yogg-saron). This not only hurts the group by losing a friendly player, but said player can also kill other players while insane.
** On top of that, every so often players have to go inside Yogg-Saron's mind and attack his BRAIN while he's casting an induce madness spell. Failing to get out of Yogg-Saron's head in time will cause the people inside to instantly go insane.
** Inverted with Meng the Demented of the Spirit Kings encounter, who has an ''In''sanity meter. He alternates between attacking the tank and running away while reflecting his attackers' damage back at them; how full his meter is determines how damaging his abilities are, and when it fills, he changes tactics.
* Several variants of ''VideoGame/{{Angband}}'' implement a sanity readout, usually in the form of "Current Sanity/Max Sanity" due to the typically text-based nature of said games. Notable variants include ''CthuluBand'' and ''TalesOfMiddleEarth'', which borrows a number of elements from the former.
* ''VideoGame/LoneSurvivor'' has a hidden but very extensive meter, tracking almost everything the player does, and leading into one of three endings. ([[http://www.rockpapershotgun.com/2012/04/23/building-fear-lone-survivor-interview-part-one/ In the alpha, it tracked negative actions]], but responses to the original trailer convinced the dev to add positive actions as well.) In general, sleeping well, eating right, and interacting with other living things will boost the meter, while using pills, staying up when tired, and killing rather than avoiding monsters will decrease it.
* In ''VideoGame/DontStarve'', your character has a sanity meter that slowly erodes as you GoMadFromTheIsolation. There are some things that make it go down quicker, like eating raw meat or [[MushroomSamba mushrooms]], and some things that can make it go back up, like consuming [[HyperactiveMetabolism good food cooked in the Crock Pot]], creating a new prototype with the Science Machine or Alchemy Engine, or wearing a garland of pretty flowers. As your sanity goes down, various dark shadowy creatures start to randomly phase in and out of view... and when it gets really low, they [[OhCrap all turn hostile.]]
* In the horror game VideoGame/KnockKnock, after you reach the final levels, the game gets a massive [[DifficultySpike difficulty spike]] and gives you a Sanity Meter, which drains while you're in the woods and if you are touched by the Guests. What makes it specially bad is that, by the ending, if the bar is very small or empty (there are no ways to refill it), you will get a Game-Over the instant you attempt to leave the house, preventing you from finishing the game and having to start over [[spoiler: unless you turn on all of the house's lights, [[GuideDangIt which is not told anywhere in the game]]]].
[[/folder]]

[[folder: ChooseYourOwnAdventure]]
* In the FightingFantasy book ''House of Hell'' you collect FEAR points when something eerie happens. If your total ever equals or exceeds your FEAR score, you instantly die.
** Notably, it's literally impossible to get through the book if you roll poorly on your FEAR score - you must score at least 7 points, which is the minimum FEAR score.
* Rick Fortune of the DiceMan game comic series had a Sanity score - dropping to zero or below ended the game as you went mad. A character you were protecting so they could testify in court in one scenario also had a score - letting it drop too low meant you failed as they turned into a gibbering wreck unable to do so.
[[/folder]]

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