Sanity Slippage: Literature

  • In A Symphony Of Eternity one of the main characters Metternich per Pelasgiamus, who after a hellish fleet battle he debriefs his commander Field Marshall Cornelia. The Field Marshall informs him that because he won the battle and captured the enemies leading Admiral had made the enemy retreat to their strongest Space Fortress and their predominant strategy was to draw the out makes Metternich's huge victory actually detrimental to their cause. Combined with the fact that this particular fight was a very hard one in which his force of about 350 ships somehow defeated and captured a foe that numbered 18.000 ships makes him almost crack from madness and he imagines jumping over the Field Marshall's desk, strangling her and bashing her head into the floor untill it becomes a puddle of goo. What's even more disturning is the fact that he's not a profesional soldier, rather he's a civilian potions maker who was forcifully drafted into the war and is quite polite, charming and funny to those around him. Though the war is taking it's toll on him.

  • In Dragon Bones, Ward's mother is already a Cloudcuckoolander at the start of the novel, but gets worse over the course of it. In the end Ward can't find her anymore with his magical ability to find people, even though her body is there. She's gentle and nice the whole time, but lives in a world of her own making, and refuses to acknowledge the reality (which is not really worth living in, at least before the death of her abusive husband).
  • Johnny Truant and Zampano in House of Leaves.
  • Gollum and Denethor in The Lord of the Rings. Also, Isildur after he gets the Ring. Boromir, particularly after Lórien.
    • What, you forgot Frodo?
    • Thorin deserves a mention, his desire for gold applied this trope to him. Thankfully he regains it in the end
  • Jack Torrance in The Shining. Stephen King stated his book was about a normal man who goes crazy, and that Stanley Kubrick's film was about a crazy man who goes absolutely bonkers.
    • Stephen King loves this trope. Bag of Bones and the short story "The Ballad of the Flexible Bullet" are about men who clawed their way back from the brink of insanity. The short story "The Jaunt" is about a teleportation machine that causes insanity if it is used incorrectly.
  • Roland goes through this in the first third or so of The Waste Lands due to the paradox he created by preventing Jake's (first) death in The Drawing of the Three. He gets better after being reunited with Jake.
  • Rand Al'Thor of The Wheel of Time certainly seems to inhabit this trope over the course of at least seven Doorstoppers. More pressures, more sacrifices and mistakes, more obvious signs of mental instability. After he is almost captured by legendary psychopathic torturer Semirhage and forced to almost kill Min he snaps completely. He adopts Dissonant Serenity and engages in more and more questionable deeds. After almost killing his own father, willingly, out of misplaced rage and paranoia, followed by a bit of fatalist Straw Nihilist monologuing on the site of his death in a previous incarnation 3,000 years earlier he seems to be showing signs of addressing the slippage though.
  • The narrator from The Moth Diaries. Possibly.
  • Everyone in The Republic Of Trees:
    • Alex: becoming a Psycho for Hire for whoever holds the power - though truth be told, he just needed a little push
    • Isobel: completely breaking down from Joy's Mind Rape - which we get to read in painful detail... except the "therapy reports" are written completely in newspeak.
    • Louis: getting more and more lost in his vision of the Revolution, overlooking obvious flaws until everything collapses around him
    • Joy: a meek girl with self-image problems, using her intelligence to get to power and ending a Knight Templar. Then she realises that she could actually have a boyfriend and it drives her completely Yandere over a couple of chapters.
    • Michael, the most notable, being the narrator: over a couple of chapters he suffers severe head trauma, discovers alcohol, discovers that the girl of his dreams is a slut and what's worse, she only started an affair with him to get back at his brother... he starts hearing voices, having memory gaps... By the end of the story he is so broken, that when he discovers what he is now a boyfriend to a Yandere and they just murdered his ex in cold blood , he decides to just roll with it.
  • The narrator of "The Yellow Wallpaper". Understandable, when you're locked in the attic for months, almost totally deprived of outside interaction.
    • Of course, a popular theory is that the "attic" in question is actually a room in a mental hospital, and that the narrator is already insane when the story begins.
  • Very common in H.P. Lovecraft's work, most notably in "The Rats in the Walls" and "The Shadow Over Innsmouth." Of course, considering the type of stories he wrote, it's understandable.
  • Warrior Cats: Hollyleaf, and to a lesser extent, her brothers. Bluestar in the original series also goes though this after Tigerclaw's betrayal.
  • Most Redwall books have at least one villainous character go through this.
  • In Fall of Damnos, Sahteh the Enfleshed, a lord of Necron Flayed Ones, finds himself less and less self-aware as his craving for a new skin grows stronger. By the end, he can't tell whether he's still alive or already a killer robot, doesn't know what planet he's on and thinks of nothing but getting a new skin.
  • Alicia DeVries of In Fury Born suffers this throughout the second half of the book due to being possessed by the last of the Greek Furies. Culminates when she discovers the identities of the traitors within the Imperial Fleet, and subsequently goes batshit crazy. Fortunately, she is stopped from ramming a space station with nine thousand innocents and The Big Bad aboard by the Fury and her ship's AI in a Battle in the Center of the Mind.
  • Dr. Seward in his appearance in Anno Dracula. You have to give him a little insanity though; it's an Alternate History of Dracula where instead of the Earn Your Happy Ending situation of rescuing Britain from a supernatural evil while losing (only) your fiancée and an American friend, he lives through a Diabolus Ex Kill 'Em Or Corrupt 'Em scenario.
  • In the original Dracula, Jonathan Harker and Renfield experienced this thanks to the Count. Harker recovered; Renfield, not so much.
    • Renfield started out as a mental patient with a fixation on eating life. Dracula makes him considerably worse, but Renfield does recover enough to try and save Mina from Dracula though he's killed for his trouble.
  • In Diary of a Madman, the eponymous diary details the descent of Poprishchin descent into madness, starting with his delusion that he can understand dogs and their letters.
  • Alfred Lambert in The Corrections.
  • Happens to a few characters in The Pale King, most notably David Cusk and Lane Dean.
  • In Max Barry's Machine Man, the main character, Dr. Charles Neumann, suffers from this. While not quite 'normal' to begin with, after he's replaced both legs and one hand with Better Parts, he starts talking to them and referring to himself as "we".
  • Jaimy in the Bloody Jack series. Early in My Bonny Light Horseman, he receives a head wound in battle that doesn't get treated for weeks because he's in a French prison. As the series progresses, you can see him slowly spiraling down to his Heroic BSOD in The Mark Of The Golden Dragon.
  • In Thérèse Raquin, the more time passes, the more Thérèse and Laurent are haunted by memories of Camille, and the crazier they become.
  • A Song of Ice and Fire:
    • Theon's Point of View chapters in A Clash of Kings show him becoming increasingly more terrified and paranoid, making ever more desperate decisions as he realizes that the reinforcements he needs aren't forthcoming.
    • While Cersei had never been completely grounded, she wasn't completely off her rocker either. Over the course of the fourth book, though, in response to the death of her firstborn son and shortly afterward her father as well, she starts losing it, seeing enemies in every corner and ordering people tortured willy-nilly.
  • The Bursar of Unseen University from Discworld used to be quite sane, up until the appointment of Mustrum Ridcully to Archchancellor wore away at his nerves. His sanity really took a dive in Reaper Man, when ancient wizard Windle Poons rose from the grave. In fact, it's so bad that the medication he's given is specially designed to make him hallucinate sanity.
  • Duane Hoover in Kurt Vonnegut's Breakfast of Champions gradually loses his sanity throughout the novel and is pushed over the edge when he takes a Kilgore Trout short story as the truth and believes he is the only real person on Earth.
  • Star Wars Legends:
    • In the X-Wing Series Lara Notsil, AKA the former Imperial agent Gara Petothel, slowly goes through one as she becomes the mask after infiltrating Wraith Squadron. It turns out that Imperial Intelligence was... lax in concerning themselves with what would happen to an agent after having so many different identities swirling around in their head. She manages to never show it, but some of her inner dialogue is downright depressing as she fights between her two /three different identities in order to stay with her Squadron.
    • Palpatine from Dark Empire. Pre-Endor Palpatine had been scarily sane, but the ordeals of death, Body Surfing, and the natural mental instability of clones leads him further down the slope throughout the course of the story.
    • In Timothy Zahn's Thrawn Trilogy, Joruus C'Baoth was always insane, but generally did a good job keeping that fact concealed. His control slips drastically by The Last Command.
  • Happens to Ron in Harry Potter and the Deathly Hallows, whenever he wears the locket.
  • Katniss Everdeen progressively starts to lose it over the course of The Hunger Games trilogy.
  • In Under a Graveyard Sky, Faith goes a little into this after they board a yacht that was taken over by the mercenaries hired to protect it and sees the carnage that followed, killing and rape everyone there. It becomes more serious when they're clearing a cruise ship later. Oddly it's not fighting zombies that does it but what she finds after the zombies are cleared out, the horror shows in the cabins, even the ones where they find survivors. She turns Trixie, a teddy bear they found on one ship into a Companion Cube as a coping mechanism.
  • In the Newsflesh series, Shaun has a bad case of slippage after being forced to shoot his sister when she's going into amplification, i.e. becoming a zombie at the end of the first book, Feed. Over the course of the next two, Deadline and Blackout, he goes from having conversations with Georgia to outright visual and tactile hallucinations. He's well aware he's clinically insane, and prefers it to sanity, since dealing with the reality of his situation would push him to suicide.
  • A consequence of syphilis in The Kingdom of Little Wounds. The queen has probably been losing her mind for years, and she only appears to get worse over the story.
  • The Stormlight Archive:
    • Szeth-son-son-Vallano is a pacifist who is also a Truthless—a sort of warrior-slave of his people, bound to obey anyone who holds his Oathstone. He is also quite possibly literally the most dangerous man on the planet, partly because he's the first Surgebinder to be seen in four thousand years. He, understandably, is typically used as a weapon and assassin, which is made worse by the fact that there is nothing magical about his oath; he could stop the murders at any moment if he would just choose what is right over the law. By the second book, his brain is barely hanging on by a thread. It gets worse when he finds out that the "lies" he told that got him made Truthless were actually true all along, meaning absolutely none of it was necessary.
    • The Heralds, who have been wandering the world for four thousand years after giving up on their oaths, are getting crazier. Shalash (Herald of Beauty) has taken to destroying any artwork depicting her, Nale (Herald of Justice) is obsessed with law to the point of being willing to kill a girl over petty theft—but stopping the instant she is pardoned, and Kalak has become a paranoid wreck jumping at shadows.
      Kalak: I'm worried about Ash.
      Nale: You're worried about everything.
      Kalak: She's getting worse. We weren't supposed to get worse. Am I getting worse? I think I feel worse.
  • The Big Bad of the Heralds of Valdemar series suffers steadily worsening sanity as he Body Surfs through the centuries, as a result of spending his time between bodies in a Soul Jar in the Void Between the Worlds. As Ma'ar and Leareth he's a fairly Magnificent Bastard, but by the time we see him as Mornelith Falconsbane in the Winds trilogy he's grabbed the Villain Ball tight and won't let go. The slippage accelerates when he's flung into the Void bodily between Winds of Change and Winds of Fury, leading to his final downfall.