Sanity

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. When sanity hits zero, a player becomes completely insane.

Madnesses

Affliction	Description
Delusions	Causes intermittent hallucinations that will obscure monsters' true form. At lower levels of sanity, monsters will appear to change forms randomly.
Real Delusions	Causes shapechangers and lycanthropes to polymorph into the player's delusions.
Sanctity	Intermittently causes a player's attacks against female humanoids and centaurs to fail or deal reduced spell damage.
Gluttony	Causes increased hunger.
Spores	Causes intermittent hallucinations, confusion, stuns, damage, and ability score drains. Does not affect Androids or Clockwork Automatons.
Frigophobia ("fear of cold")	Intermittently causes a player to panic and lose turns after taking cold damage or moving over ice.
Cannibalism	Intermittently causes a player to vomit after eating vegetarian or vegan food; players will not always be consistently warned before committing further cannibalism.
Rage	Causes reduced AC, reduced spell success, and increased damage.
Argent Sheet	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	Intermittently causes greatly reduced AC.
Nudist	Causes reduced AC, DR, accuracy, healing, power regeneration, and spell success for each piece of equipment.
Ophidiophobia ("fear of snakes")	Intermittently causes a player's attacks against serpentine monsters to fail; player will intermittently panic and lose turns after being poisoned. Causes players to take increased damage from serpentine monsters.
Arachnophobia ("fear of spiders")	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")	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")	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 and lose turns.
Paranoia	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	Intermittently causes a player to panic and lose turns after losing or releasing an item.
Cold Night	Intermittently causes a player to slip over non-existant ice. Intermittently causes air around a player to freeze solid, destroying potions in a player's inventory.
Overlord	Intermittently causes a player to feel the burning gaze of the Overlord, causing weakness and burning possessions.
Dreams	Intermittently causes a player to pass out and dream of strange cities, suffering damage, stunning, and reduced sanity.
Helminthophobia ("fear of being infested by worms")	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	Intermittently causes tentacles to erupt from your brain during your attack, causing additional melee damage and further degrading sanity.