Sanity is a feature specific to dNethack. It represents the player's mental well-being in response to the various horrors encountered during the game.
As a player's sanity rating drops below 100, a player becomes susceptible to various delusions, compulsions, and conditions that may be inflicted during the game.
Major spoilers for dNetHack are contained below this point. Read further at your own risk.
Encountering sanity-taxing monsters
The first time the PC senses a new species of sanity-taxing monster (whether by seeing it from a distance or moving adjacent to it), they suffer an episode of acute sanity loss, losing between 1 and the monster's difficulty points of sanity. This acute sanity loss is recorded, and determines how "stressful" the PC finds that type of monster. This episode of acute sanity loss may also inflict a temporary madness effect (see below).
Whenever the PC senses a species of sanity-taxing monster that they have already encountered, the PC will lose up to 1 point of sanity per turn until their current sanity is less than or equal to 100 - the "stress" value. This passive sanity drain will never inflict a temporary madness effect.
Beginning a turn next to a visible walking delirium inflicts between 1 and 8 points of sanity loss ("The walking delirium takes on forms new and terrible!"). This sanity loss may also inflict a temporary madness effect (see below).
Beginning a turn next to a mad-templated monster in a lit square or hearing the monster scream inflicts a lesser amount of monster-difficulty-dependent sanity loss ("The x's shadow takes on forms new and terrible!"/"The x screams in madness and fear!"). This sanity loss may also inflict a temporary madness effect (see below).
An apocalypse angel's attack may inflict between 1 and 8 points of sanity loss ("The truth shakes the foundations of your mind!"). This sanity loss may also inflict a temporary madness effect (see below).
The Elder Priest
The Elder Priest's tentacle attack may inflict between 1 and 24 points of sanity loss, and may also inflict temporary madness effects (see below).
Natural sanity regeneration
Sanity recovers naturally up to a threshold determined by the character's Wisdom score and modified by a number of factors. Sanity recovers quickly (1 point per 10 turns) up to 1x the modified wisdom score, somewhat slower (1 point per 32 turns) up to 2x the modified wisdom score, and more slowly still (1 point per 100 turns) up to 3x the modified wisdom score.
Natural sanity regeneration will never *lower* your current sanity score, even if penalties result in a negative effective wisdom.
Modifiers to effective wisdom
- If the veil is intact, the PC receives a +10 bonus wisdom.
- If the veil has been pierced, the PC suffers a penalty equal to the log-base-two of the PC's insight.
- If the PC has the Transparent Sea thought, they receive a +30 bonus.
- Elves receive a +3 bonus.
- Orcs suffer a -3 penalty.
- Binding Orthos inflicts a -5 penalty.
- Wearing equipment that imposes a healing penalty ("You feel itchy.") imposes the same penalty to effective wisdom as well.
- Certain roles receive a modifier to effective wisdom:
|Binder||Bonus equal to the spirit power die size|
- Certain places impose a penalty:
|Other locations in the Depths||-10|
|Android Anachrononaut quest "home" level||-15|
|Android Anachrononaut quest "locate" level||-30|
|Other Android Anachrononaut quest levels||-10|
|Standard Anachrononaut quest "home" level, after the leader is dead.||-30|
|Standard Anachrononaut quest levels||-10|
|Drow Nobleman quest "nemesis" level||-30|
|Hedrow Nobleman quest "home" and "nemesis" levels||-30|
|Hedrow shared quest "nemesis" level||-30|
These are the various afflictions, or "madnesses", that can take effect as your sanity is lowered:
|Panicking||The most common effect. Base accuracy is reduced to -5 (overriding all to-hit bonuses from level), and all the PC's attacks do half damage. Spell failure rate is set to 100% for all spells that are not emergency spells or from the escape school. Wand power skill is reduced to base level. The PC gains two bonus movement points per round (+1/6th of the base movement rate). The player should consider running away from combat while their character is panicking.|
|Stumbling Blindly||The character acts as though blind and confused.|
|Staggering in Shock||The character acts as though stunned.|
|Babbling||The character begins babbling incoherently, preventing the casting of spells and the reading of scrolls, spellbooks, and syllables. Creatures within a range of squares nearby - equal to 1⁄3 of the character's constitution score - learn the character's exact location. The character is also unable to #chat to monsters.|
|Screaming||The character begins screaming, preventing the casting of spells and the reading of scrolls and spellbooks - however, syllables can still be read while screaming. <stub: effects of "song noise">. The character is also unable to #chat to monsters.|
These madnesses are mostly conferred by seeing certain monsters, usually demon lords/princes. Detecting the monsters through telepathy, monster detection, and so on (probably?) does not give you the madness, unless they are adjacent.
|Delusions||Daughter of Bedlam and Walking Delirium||Causes hallucinations that will obscure some monsters' true form. At lower levels of sanity, more monsters will appear to change forms randomly. Madmen start with this madness.|
|Formication ("a sensation like insects crawling over the skin")||Akkabish tannin||Reduces your skills and increases your spell failure rate proportional to lost Sanity. Sometimes causes you to wake up from sleep.|
|Host||Shalosh tannah||Intermittently lowers your dexterity to 3. Sometimes also causes you to become nauseated.|
|Sciaphilia ("the love of shade")||Nachash tannin||When not standing in a partially lit square, reduces to-hit and increases spell failure proportional to lost Sanity.|
|Dissolving Mind||Khaamnun tannin||Increases the rate at which you forget spells, and sometimes causes you to lose 1 to 4 levels and suffer amnesia proportional to the levels lost. This drain will never be fatal (though, that may be cold comfort).|
|It's too BIG||Raglayim tannin||Intermittently prevents you from casting spells, playing music, speaking, or using spirit powers.|
|The Rotting||Sartan tannin||Intermittently creates stinking clouds around you. Lowers your charisma proportional to Sanity lost|
|Apostasy||Teraphim tannah||Intermittently lowers your alignment record. Sometimes reduces your maximum alignment or angers your god as well. Frequently prevents prayer. For roles that cast spells using their wisdom score, also frequently prevents the casting of spells.|
|Real Delusions||Aldinach||Causes some monsters to polymorph randomly. At lower levels of sanity, more monsters will change forms. Only monsters that can randomly generate will be affected.|
|Sanctity||Alrunes||Intermittently causes a player's attacks against female humanoids and centaurs to fail or deal reduced spell damage.|
|Gluttony||Juiblex||Causes increased hunger.|
|Spores||Zuggtmoy||Causes intermittent hallucinations, confusion, stuns, damage, and ability score drains. Does not affect Androids or Clockwork Automatons.|
|Frigophobia ("fear of cold")||Kostchtchie||Intermittently causes a player to panic after taking cold damage or moving over ice.|
|Cannibalism||Yeenoghu||Intermittently causes a player to vomit after eating vegetarian or vegan food; players will not always be consistently warned before committing further cannibalism.|
|Rage||Baphomet||Causes reduced AC, reduced spell success, and increased damage.|
|Argent Sheen||Graz'zt||Intermittently causes monsters to panic, lose turns, and gain reflection for a turn; causes players to deal reduced spell damage to monsters. Additionally, intermittently causes players to stop and admire oneself in a mirror, losing turns. Causes increased damage from male humanoids and centaurs.|
|Suicidal||Orcus||Intermittently causes greatly reduced AC. Consistently causes you to take extra damage in combat.|
|Nudist||Malcanthet||Causes reduced AC, DR, accuracy, healing, power regeneration, and spell success for each piece of equipment.|
|Ophidiophobia ("fear of snakes")||Shaktari||Intermittently causes a player's attacks against serpentine monsters to fail; player will intermittently panic after being poisoned. Causes players to take increased damage from serpentine monsters.|
|Arachnophobia ("fear of spiders")||Avatar of Lolth||Intermittently causes a player's attacks against female humanoids, centaurs, and spiders to fail or deal reduced damage. Causes players to take increased damage from female humanoids, centaurs, and spiders.|
|Entomophobia ("fear of insects")||Obox-ob||Intermittently causes a player's attacks against insects and arachnids to fail. Players take increased damage from insects and arachnids.|
|Thalassophobia ("fear of the sea")||Dagon||Intermittently causes a player's attacks against aquatic monsters to fail, cause reduced attack damage, or cause reduced spell damage. When attacked by aquatic monsters, players will take more damage and will intermittently panic.|
|Paranoia||Demogorgon||Intermittently causes a player to attack a monster's hallucinatory twin instead of the monster itself. Causes a player to have a hard time discerning the location of unseen monsters.|
|Talons||Lamashtu||Intermittently causes a player to panic after losing or releasing an item.|
|Cold Night||Baalphegor||Intermittently causes a player to slip over non-existent ice. Intermittently causes air around a player to freeze solid, destroying potions in a player's inventory and potentially causing fatal suffocation.|
|Overlord||Asmodeus||Intermittently causes a player to feel the burning gaze of the Overlord, causing weakness and burning possessions. The madness is only conferred upon Asmodeus' death, rather than seeing him.|
|Dreams||Great Cthulhu's mind blast||Intermittently causes a player to pass out and dream of strange cities, suffering damage, stunning, and reduced sanity.|
|Non-euclidean Angles||Observing Great Cthulhu's teleportation power||Intermittently allows monsters to move through strange angles. Such monsters ignore AC from worn armor and all DR, and can teleport as though they were tengu.|
|Spiral into Madness||Great Cthulhu's Wisdom-draining gaze attack||Intermittently abuses Wisdom, and sometimes also lowers Sanity by 1 point.|
|Helminthophobia ("fear of being infested by worms")||The Elder Priest||Intermittently causes a player's attacks against worms and tentacled monsters to fail. Causes players to take increased damage from worms and tentacles.|
|Goat-Ridden||Potions of Goat's Milk||Intermittently causes tentacles to erupt from your brain and attack adjacent monsters, causing melee damage but further degrading sanity. See The Black Mother for further information.|
|Masks of Nyarlathotep||Nyarlathotep||When you kill monsters, they will sometimes "drop their mask" and transform into a random summoned U. As summons, these U will disappear after a few turns.|
The following actions will quickly restore sanity:
- Drinking a potion of sleeping (taking a 'sedative'). Blessed potions restore 15 sanity, uncursed 10, and cursed potions 5.
- Using an effigy will restore half the sanity needed to get you back to 100.
- Successfully reading the Necronomicon or the Book of Lost Names will restore 1 sanity. A failed reading will cause you to lose 1 sanity instead.
- Killing a monster that would also increase your Insight rating.
- Drinking a noncursed potion of restore ability; blessed potions heal 20 sanity, while uncursed ones heal 5.
- Drinking a potion of booze of any beatitude restores 5 sanity. Past your drunkenness limit, this only goes to a maximum of 50 sanity.
- Receiving a course of tranquilizers from a nurse. This behaves like a blessed sleeping potion, with 15 sanity restored per course.