Fear is a part of existence, and in its true form is not pleasant to experience. Scared people are prone to knee-jerk decisions, which is understandable. However, not all fear experiences are created equal. Some fears are immediate, apparent, and deep... and others are based around vague possibilities, whispers, rumors, stuff that could happen with variable or unknown odds. It is a low, background fear that lurks in the back of your mind, the classic paranoia. And sometimes, people just can't live with it and do something to assuage it. When this actually has some merit, then the sufferer is Properly Paranoid.
But many times, it doesn't. It is also always an overreaction. Not that that matters. All that matters to the sufferer is to assuage that fear.
This is not The Paranoiac. That trope's examples are demonstrated to be paranoid all the time, about everything, so they're afraid of everything. And often, such behavior will result in purely defensive reactions (going off the grid, tinfoil hats, etc) or constant belligerence in an attempt to destroy threats before they can develop. This trope is about when people are unable to live with the mild fear of certain possibilities and end up making decisions that not only affect other people negatively but very often end up causing the exact situation they feared to come to pass. This is especially prevalent if the being who does it should be smart enough to see the very clear possible backfires and downsides (or has direct past experience of these kind of actions not working), but does it anyway.
The end result is never good. In fact, it almost always ends in a Self-Fulfilling Prophecy (either directly causing something bad to happen, or making everybody else hate the paranoid person and seek to destroy them), and/or Nice Job Fixing It, Villain, Nice Job Breaking It, Herod, and all the tropes in that vein (they're also incredibly vulnerable to Paranoia Gambits and are often what said gambits aim to achieve, though using one might end up backfiring in turn because of the severe overreaction that can occur). All because they can't live with their fear, however mild and background and running on long odds it may be. Can also lead to Bullying a Dragon, and the consequences of that trope as well. If carried out after the fear has manifested, but still blown significantly out of proportion, this kind of reaction counts as Disproportionate Retribution. These characters also very firmly believe that There Are No Coincidences and more often than not they are victim of the "no, it was a coincidence and you ruined your life by assuming otherwise" variant.
- Mobile Suit Gundam SEED Destiny: Big Bad Durandal is so paranoid about the possibility that Kira Yamato and Lacus Clyne might stand in his way (partially because they're such wild cards he can't figure out how they'd react to his actions) that he tries to have them assassinated. Ironically, Kira later observes that he and Lacus initially agreed with Durandal and would've been willing to go along with his plans, but considering he just attacked them out of the blue without warning, they took great offense.
- JoJo's Bizarre Adventure: Golden Wind: The Big Bad of the arc, Diavolo, believes everyone is out to get him, and conceals his identity using multiple layers upon layers to avoid any assassinations. Soon enough, people do begin to look into his identity to get him, but he brought that upon himself by first stiffing his Hitman Team from a well-deserved pay (causing them to look into his identity, which intensified after he killed 2 of their members as a warning), and then eventually attempting to kill his own daughter on the slight chance she might be used to divulge his identity, causing one of his most efficient capos to turn on him. Eventually, The Heroes do use Trish to peer into Diavolo's past, but it's only because they wanted to protect her from her evil father by killing him first.
- Kamen no Maid Guy: Played for Laughs as a Running Gag. Anything and anybody that approaches Naeka Fujiwara (an Ordinary High-School Student who inherited millions) is suspected by Kogarashi (the titular "Maid Guy", a Kenshiro-esque superhuman martial artist hired to protect her) to be performing some kind of plot to hurt her and pre-emptively answers in "kind" to obtain information on said "plot", forcing Naeka to smack him before he can go past the part where he's threatening to hurt someone and actually hurts someone.
- In One Piece, this is taken to extreme and horrific levels with the destruction of Trafalgar Law's homeland of Flevance. When the citizens all come down with horrifying Amber Lead Syndrome from decades of mining said poisonous lead, everyone assumes the worst and that it's contagious, forcibly sealing the town in and gunning down anyone who tries to escape, out of fear for their safety, unaware that the disease is only hereditary, not contagious. Unfortunately, nobody believes those who try to explain this, and when the citizens try to force their way out, the surrounding countries take it as a reason to commit justifiable genocide. Even worse, Law's childhood friends are massacred as well, despite the fact that they were promised to be spared.
- In Happy Heroes, Oversensitive S. has a tendency to overreact and jump to conclusions way too easily. He opposes the Planet Xing Supermen for a time due to this, thinking they're up to no good.
- Any storyline that involves plans made by superheroes to take out other superheroes (e.g. Professor Xavier's Xavier Protocols and Batman's plans in Justice League of America: Tower of Babel) can come off as this to the targets. Often, it's acknowledged it's a good idea to know how to take down other heroes in case of things like mind control, but quite often the problem is the person planning the contingencies doesn't let the others know or abuses the trust of the others to come up with them.
- While not completely unjustified, the plots regarding many General Rippers trying to get rid of Superman (for example, New Krypton) nine times out of ten (and this is being pretty generous on their behalf) are triggered because they go past mistrust and straight into deciding the only solution for whatever problem is occurring is to just murder the Kryptonian and anybody unlucky enough to either be in the kill zone or in the way of getting it approved. They never put the same amount of effort into stopping actual well-known alien threats, and in some cases are willing to ally with psychotic terrorists and/or other aliens that have made clear repeatedly that they will try to conquer Earth the moment Superman is dead to get rid of "the greater threat" that is the man occasionally labeled "the Big Blue Boy Scout". This trope extended to the animated continuity of the DC Universe as well; see below.
- Red (2003) (though not the movie, which is very different) has this drive the whole plot. Paul Moses is a retired CIA agent who has done many, many bad things for the sake of his country, but is now an old man content to quietly live away his final years in isolation. Then the CIA gets a new director, who learns of Moses' existence and deeds, and completely freaks out over them, and more specifically, what could happen if anyone found out. Never mind that Moses is tucked away counting his days until death; the fear of the possibility is too much and said director orders Moses' assassination. And things go downhill from there...
- Firestorm villain The Weasel was a former Stanford student who was kind of an asshole, and eventually got a job at a university with four people who were also from Stanford. Fearing that they disliked him and were planning to ruin his career, he donned a weasel costume and tried to kill them all. Turns out, none of them even remembered him, much less plotted revenge. All he manages to accomplish is ruining any non-villainous career when Firestorm gets on his case.
- There's a zig-zagged case in Ultimate Spider-Man: When Spider-Man attacks the enforcers, Montana wants to take him out of the building, quickly, and close the door. The guy must be a trap from the feds. Ox says that no, he must be just a guy on his own doing stupid things. Eventually, the feds do show up, but on their own; Spider-Man's attack was not related to them and even interfered with it.
- Wish Carefully is about all of Wizarding England falling to the Death Eaters by having Harry Potter give them everything they wanted — exiling all Light supporters, no muggles, and no-one else can interfere. Then Harry just sits back and lets the Death Eater philosophy run to its logical conclusion. In his notes, Lucius Malfoy calls this sort of planning "Slytherin-like" and admits that it was a coldly calculated move that the Death Eaters were all too happy to accept. By the time the story starts, what's left of Wizarding England is on the verge of complete collapse due to Voldemort and the Death Eaters' own magically-binding policies doing them in. This had the effect of making Voldemort paranoid of everyone around him, causing Voldemort to randomly torture people with the Dark Mark, prevent anyone from talking to him unless they wholeheartedly agree that he's a genius, and has killed people for wearing glasses (thinking it might be Harry mocking him). The story ends with Lucius and another group of Death Eaters planning to kill Voldemort (or deliver him to Harry so that he can kill him) because of how rampant Voldemort's paranoia has become.
- RainbowDoubleDash's Lunaverse: Archduke Fisher, in regards to Corona. He's convinced that every action must be taken to shore up Equestria and prepare to confront her, lest she go on a mad rampage, burning every city to the ground. The fact that she quite easily could do this anyway and hasn't never occurs to him, and ends up getting him canned after one too many law broken in the name of "the greater good". He also never suspects that his secretary is a changeling.
- Many of Ami's problems in Dungeon Keeper Ami could be avoided if the surface world took her at face value when she says that she's not evil. The problem is that Ami is a Dungeon Keeper when literally every other Dungeon Keeper is Always Chaotic Evil, and paranoia is usually the proper response to them. Everything she does, no matter how altruistic, is assumed to be a ploy of some sort for when she inevitably turns on them.
- Washington in Recovery None devolves into this after being repeatedly betrayed by people he thought he could trust; by the time he runs into York and South, he's convinced everyone and everything is out to get him and the Reds and Blues and he nearly kills them before they talk him down.
- In To Foil Haru Okumura's Evil Schemes, Ren Amamiya is convinced that the new team member Haru is secretly hiding dark intentions and is targeting Ryuji as the weak link thanks to the time she spends with him. He has no idea that Haru is hanging with Ryuji because she has a crush on him.
- Mac Bethad in A Thing of Vikings. His failure to see that Stoick and Hiccup aren't like other Norse leaders he is used to dealing with resulted in him being convinced they were eventually going to annex his kingdom and he should strike first to prevent it. His paranoia ended up being his undoing and the basis of a morality tale for generations to come.
- The Dragon and the Butterfly:
- Tragically, Hiccup spends a lot of time in the Encanto walking on egg-shells, worried that one false move will end with everyone hating him like it was on Berk.
- On the lighter side, when Hiccup finds out that the Madrigal House is alive, it sets him on edge to the point where he's worried it would eat him. It isn't until they finish rebuilding Casita that he mellows out.
- When a Wolf Runs Alone: Luz is afraid about what might happen in the event that someone discovers that she is a werewolf. While such a reveal would be terribly dangerous back on Earth, no one on the Boiling Isles finds it shocking or frightening, as such creatures are commonplace in the demon realm. Luz is only insistent on keeping it a secret as a learned habit, both because her family taught her to keep it secret and having been a frequent victim of bullying.
- End of Days has this as a small sub-plot: it's bad enough that Arnold has to protect the devil's chosen bride against Satan himself and a New York where every third person is apparently a devil worshiper, but he also has to deal with a subset of priests who want to just kill the devil's bride to remove any chance he can bring about the end of the world with her (even if it's not a permanent measure they simply don't care as long as it doesn't happen within their lifetimes). Even another priest calls out the wrong-headed nature of this reaction.
Father Kovak: You can't prevent evil by doing evil!
- Doctor Strangelove: The original General Ripper decides to nuke all of Russia because of an alleged Russian plot to make Americans unable to have sex. In an era where Communist Russia literally had dastardly plans going on, he still decides to jump to the most improbable theory possible (fluoride in water added by a Communist conspiracy) for his sexual inadequacy instead of more probable reasons like stupid people manning the aqueduct (if the fluoride theory is true) or his own bodily health (too much drinking and smoking, or maybe him being too old to find women attractive anymore). In essence, Ripper decides to start World War III because he can't stand the idea that he has become impotent solely on his own choices.
- Hercules (2014) has King Eurystheus. In this version of the story, Hercules didn't kill his family due to Hera driving him mad; instead, Eurystheus drugged him and had a pack of wolves kill his family while making Hercules think he had done it. Why? Because Hercules was lauded as a great hero and the son of Zeus, and he believed that eventually the people would call for him to be king. He figured that killing Hercules would make him a martyr, so he decided to ruin his life and name instead. What really drives this home is that Hercules had zero interest in being king and says so outright (that he "wanted nothing"); Eurystheus, clearly projecting himself onto the hero, counters with this bit of Insane Troll Logic.
King Eurystheus: Precisely! Your sin, Hercules, was that you had no ambition! I can deal with an ambitious man! He can be bought! But a man who wants nothing has no price!
- Enemy of the State: All of the drama that the evil NSA agents pile onto Philadelphia attorney Robert Dean is because their leader, NSA official Thomas Reynolds, sees Dean's history of helping civil unions and connections with parties that dislike the Agency and he immediately assumes that, when Dean was accidentally handed the video that showcases Reynolds orchestrating the murder of a U.S. Congressman, it was an actual deliberate action to get him arrested that Dean knuckles down and refuses to talk when Reynolds' goons arrive to his house and get too pushy with their fake interrogation just fuels this assumption. Dean, on his end, only starts taking steps once the NSA has nearly destroyed his life and are actively pursuing him on the streets with full intent to kill him.
- Marathon Man and the novel that it was based from makes it clear that Dr. Szell's paranoia is rampant and he expects people to betray him and steal his diamonds at every turn, which has made him a very hard man to deal with. "Babe" Levy's entire (literally) tortuous odyssey happens because Szell (and thus his minions) cannot believe that Levy's brother "Doc" arrived at Babe's home when he was fatally wounded by Szell in an attempt to spend his last moments with his brother and didn't provide him with some sort of Dying Clue.
- WarGames and its continuation The Dead Code both have the teenager protagonists going through great trouble (and thus Adults Are Useless) because the forces they could contact believe the teens, with their unusual skills and histories, are agents to enemy forces (Russian spies in the original, terrorists in Dead Code) rather than people that were in the wrong place at the wrong time and pissed off the wrong super-computer.
- Even if Played for Laughs for the most part, this is the Fatal Flaw of Jack Byrnes on Meet the Parents and its continuations. He is absolutely incapable of trusting anybody, not even his own family, and as a result, the "circle of trust" system he put in place to allegedly have an open "no secrets" relationship instead comes across as enforced hypocrisy. When it comes to Greg, he is not above pulling out the spy gadgets and the Truth Serum to force him to tell him "the whole truth" (that at points not even Greg knows) when he has a snafu (or just looks like he made one) because he apparently cannot believe Greg is just a Walking Disaster Area Butt-Monkey and is not actively conspiring to damage the family.
- Enchanted: When Prince Edward announces he would be marrying Giselle, his mother Queen Narissa becomes paranoid that Giselle is planning to usurp her throne and plots Giselle's exile and then death. Meanwhile, Giselle is talking about wanting to meet and befriend Narissa and prove she is a worthy new daughter.
- Blast from the Past: Played for Laughs with Dr. Calvin Webber. It's pretty obvious that being constantly paranoid is his only state of mind and if he can't feel paranoid about something, he would probably be even more crazy. It was his idea to make an advanced bomb shelter beneath his home that ironically saves the Webbers when they go down there waiting for the Cuban Missile Crisis to pass and an airplane accidentally comes crashing down on the house, but most of the dysfunction that the family develops can be tracked to the fact he feels more comfortable living in the bunker than he would be anywhere else, and when the film ends, he is starting to make plans to create another bunker in the family's new home because he cannot believe that Russia just up and quit and the Cold War is actually over.
- Harry Potter:
- As the letters from Hogwarts grow ever more numerous, Uncle Vernon takes increasingly strange measures, such as moving away from the house to a tiny island in the middle of nowhere and buying a gun. It could have ended very badly had Hagrid not taken the gun and tied it into a knot.
- There's also the Running Gag of Harry constantly believing that Severus Snape is part of any plot that is occurring on Hogwarts... and even when he was, he was Good All Along. Though Snape being an asshole to Harry almost all of the time because of old grudges regarding his father didn't help Harry trust him at all.
- After Voldemort's return, Minister Fudge absolutely refuses to believe Harry or Dumbledore trying to warn him of what's going on because he's become paranoid that Dumbledore is planning a coup. Instead, he spends an entire year smearing Harry, Dumbledore, and their allies while telling the British wizarding community that all is well. This backfires spectacularly when Voldemort appears before half the Ministry, including Fudge himself, revealing that he was BS'ing everybody; within a fortnight, everybody in Wizarding Britain has turned against him and he's kicked out of office.
- The Light Fantastic has the wizards summon Death. One of them, not liking the way Death was looking at him (i.e., Death is coming for him), proceeds to build a box with every enchantment, ward, and protective spell he can think of and climbs inside, certain he's secure. The last thing he hears is a voice next to his ear saying "DARK IN HERE, ISN'T IT?". In building his box, he did not stop to consider adding air holes.
- Amy Tan's characters often find themselves in this situation. When your mother is constantly warning you of potential disasters, you might lose your sense of agency. Several of her characters have to overcome this feeling, as they've stayed in bad situations because to take action is to take risk. In a couple of cases, the mother even helps them with this.
- A Point Horror book, The Hitchhiker, has this happen at the end. After plot twists reveal the titular hitchhiker is not the villain, the female main characters were involved in a hit and run, and the son of said victim of said fatal hit and run decided the best solution was to track down the girls, kidnap them, and feed them to a convenient lake of piranhas as revenge, the would-be avenger ends up eaten in his piranha pool. At this point, one of the girls (seemingly the only survivor at the time) decides that she has to get rid of all the witnesses to her crime and retrieves the now-dead avenger's gun to make the hitchhiker either jump into the pool or be shot. The other girl revealing herself to not be dead results in said paranoid girl ending up eaten in the piranha pool as well, when all she had to do was walk away and she might have not even been charged with her crime, considering the now-extreme extenuating circumstances around it.
- Tom Waits' poem "What's He Building In There?" is the musings of a man who believes a neighbor is up to no good because of little facts like not waving as he passes by and escalating to weird things (which the narrator may be making up) like swearing he heard someone moaning inside of the neighbor's house. The poem ends with "we have a right to know", implying that the narrator is going to go and barge into the neighbor's house.
- In The Hunger Games trilogy, even though Katniss herself had no intent of starting a revolution, President Snow believed otherwise. The brutal crackdowns organized by him out of this fear and culminating in bombing District 12 (the homeland of Katniss), combined with implied manipulations of Heavensbee, led to the revolution and Katniss becoming the Icon of Rebellion becoming a Self-Fulfilling Prophecy.
- Heralds of Valdemar: Grand Duke Tremaine is, all things considered, a decent person. Not Herald material, but the sort of man who will go to the wall for the sake of those he leads. Unfortunately, he also has the untrusting and paranoid streak that would be expected in a noble of the Eastern Empire who is A) prominent enough to be in the running for the Emperor's hand-picked successor and B) still breathing. When the Mage Storms begin while he is in command of the Imperial forces in what is left of Hardorn, his line of reasoningnote leads him to actions he realizes rather soon after the fact were not merely personally repugnant but a strategic error on the level of burning a bridge you have not crossed yet.
- Dune: There is little to no indication that Duke Leto Atreides was anything other than wholly loyal to Padishah Emperor Shaddam IV. Shaddam launched his Batman Gambit to use the Atreides' feud with the Harkonnens to destroy the former (and impoverish the latter) out of fear of Leto's "soft power" in the Landsraad. In essence, he feared that Leto planned to build The Alliance and overthrow him, pretty much because in Leto's place, that's what he would do. It bit him in the ass, big time.
- Wulfrik: Baron Udo Kruger is obsessed with the idea of his wife being unfaithful to him, to the point where he keeps a wizard on staff just to make sure she isn't being seduced when he's not around. Nothing can reassure him, including the wizard telling him there's nothing to fear or the fact that his wife is stupendously ugly. And as a result, it only takes a barbarian warlord calling him a cuckold to make him rush prematurely out of the town's defenses where his cavalry is swiftly destroyed, followed by the rest of the town.
- Doctor Who has the Time Lords, who might be the grand champions of this trope, considering how often they've done stupid things and screwed themselves over out of fear of certain possibilities, all of which are always tied up with their errant child/grand champion, The Doctor. What really drives it home is despite how old, advanced, and wise they are, and how often the Doctor has pulled their fat out of the fire, they keep finding reasons to piss him off. The Series 9 penultimate episode, "Heaven Sent", has the Time Lords (fresh off escaping back into proper reality, their survival and return only possible because of the decisions of the Doctor, at that), afraid of a prophecy of a being called "The Hybrid", and believing the Doctor knows what it is, proceed to (instead of say, contacting the Doctor and asking him) put a scenario into action that not only leads to the inadvertent death of his companion Clara, but sticks the Doctor into a pocket reality trap that he can only escape if he confesses what the Hybrid is, or he can die and take the secret to the grave with him. The Doctor refuses, believing the knowledge is far too dangerous to be shared, and instead takes a third option by using the time-resetting nature of the trap to spend FOUR BILLION YEARS breaking out of it, and when he gets out, he's pissed. How pissed? Bring down the government, willing to break the universe to undo what the Time Lords did, pissed.
- In The Twilight Zone episode "The Mirror", a revolutionary-turned-dictator inherits a mirror from his predecessor, which the man says will show a person his enemies. The new dictator becomes paranoid as he sees his friends in the mirror and kills them off. Finally, after having thrown the entire country into disarray with his paranoia, he sees himself in the mirror. Two people walk into the room to find him dead on the floor.
The last assassin. And they never learn. They never seem to learn!
- Throughout the second season of Tyrant (2014), Jamal makes increasingly poor decisions in his efforts to fight off an invasion by the Army of the Caliphate, largely because he's grown so paranoid that whenever one of his military advisers demonstrates a successful strategy, Jamal believes that that adviser might end up plotting against him.
- Orphan Black:
- Alison strongly suspected her neighbor Aynsley is spying on her for the Dyad Institute. She went out of her way to antagonize Aynsley in retaliation, to the point of making herself a social outcast. It's only after letting Aynsley die in a preventable freak accident that Alison finds out she was actually innocent, if rather nosy. She becomes crushed by guilt and quickly ends up becoming an alcoholic (though she gets better).
- Zig-zagged in the case of her husband Donnie, whom she also thought might be a spy. He was, but didn't realize it because he'd been tricked into thinking it was a sociology experiment. So when she tortured him for information, he genuinely had no idea what she was talking about. Alison figured he was innocent until she found out that he'd been in contact with Dr. Leekie, a scientist at Dyad. When she confronts him, Donnie admits to working for Leekie, but is horrified to learn what was really going on.
- The plot of the first season of Once Upon a Time is driven by Regina's fear that her adopted son's biological mother, Emma, will break the curse and try to take him away from her. Emma initially didn't believe in the curse and had no intention of trying to regain custody, but it was Regina's paranoid and over-the-top behavior that caused Emma to change her mind.
- During the last season of Star Trek: Deep Space Nine, Chancellor Gowron begins to fear that General Martok will try to kill him and seize control of the Klingon Empire (even though Martok has no political ambitions and is content with being a soldier), so he sets a Uriah Gambit in motion to get rid of Martok. Worf, however, sees through it and challenges Gowron to a duel. He kills Gowron and appoints Martok the next Chancellor, exactly the scenario that Gowron feared.
- Star Trek: The Next Generation: In the episode "The Drumhead", an accidental explosion of the Enterprise's warp core happens at the same time that it's discovered there is a Romulan spy on board and Starfleet Intelligence Admiral Norah Satie, believing this is not a coincidence (a thing she is definitely wrong about but she won't hear any facts telling her otherwise), begins a witch-hunt that threatens to destroy the careers of every single crew member of the ship (beginning with an innocent technician who's only crime is lying that he is half-Vulcan when he is actually half-Romulan for this exact reason and then going after Picard when he protests). Picard defuses the witch-hunt (and destroys Satie's career) by showing her superior officer that she's running on pure paranoia.
- The French-Canadian sketch show Phylactère Cola has an animated sketch about the inhabitants of a town getting increasingly paranoid of the local reclusive scientist, whom they suspect is behind the succeeding disappearances of a dog and a boy. Sure enough, they eventually decide to mob him, and he retaliates by unveiling a giant robot, which ends up accidentally toppling over and killing himself (alongside everyone else) during his rampage. The boy and the dog turn up after the dust settles, and then we see the name of the town on a sign: Paranoiaville.
- In the first episode of Death in Paradise, Inspector Poole discovers that the murder investigation he has been leading has been undermined by the fact that a different undercover investigation has been conducted simultaneously, both depriving him of vital evidence and leading to him inadvertently blowing the undercover operation by arresting the undercover detective. When he confronts the local police commissioner about this, the commissioner reveals that they suspect a member of the local police department of corruption, and that they couldn't risk the operation being blown by informing him. While this would normally be a perfectly valid reason for caution, as Poole himself exasperatedly yells he's only been on the island for less than a week and has spent the previous thirteen years based four thousand miles away in London, so there's probably not going to be that much risk in bringing him in the loop.
- One story arc on Homicide: Life on the Street centered around a conservative Congressman who secretly had an affair with his (male) aide. The Congressman broke the aide's arm during a fight, and became paranoid that he would expose their affair as revenge. In spite of the aide just wanting to move on with his life, the Congressman tried to frame him for kidnapping. Fortunately for the aide, he turns out to be so terrible at it that Bayliss and Pembleton are able to easily clear his name.
- Greek Mythology is full of kings whose sons/grandsons were prophesied to dethrone them, and reacted by sending the baby to be killed or walling up their daughters. In every case, they weren't paranoid enough: either the servants sent to do the deed couldn't go through or the girl was rescued by a god, ensuring the child would be a nigh-unkillable demigod.
- Warhammer 40,000:
- The Inquisition lives in between this Trope and Properly Paranoid, Depending on the Writer: any time they so much as suspect Xenos or Chaos taint, out comes the genocide measures like Exterminatus. They are willing to perform this even if it means going to war against other branches of the Imperium, such as the Space Marines (a pretty famous fluff piece of the Space Wolves involves the Marines fighting an Inquisitorial task force that had been sent to kill all of the Guard soldiers (and evacuating civilians) on a certain planet just because they were fighting against Chaos, a mission they were willing to fulfill even after the Marines told them that none of the other humans were tainted and assured them that they were willing to fight to protect said citizens). To be fair to the Inquisition, considering the consequences of being wrong and/or missing something and how rapidly it can snowball, you can't blame them for having very twitchy trigger fingers. Of course, many take this as an excuse to leave the Moral Event Horizon long in the distance...
- The Emperor was so paranoid about Xenos that he ignored warnings from the Eldar (despite the fact that he's the most powerful telepath in the universe and could have used his powers to see they were telling the truth) about his warmaster, Horus. Horus would eventually turn on the Emperor at a time when the Imperium was lacking friendly relations with everyone in the galaxy when with a little less paranoia, the Imperium could have had done an Enemy Mine with plenty of factions.
- Crusader Kings:
- Characters with the "Paranoid" trait have a tendency to see plots against themselves and their loved ones everywhere, or suspect that they're not the father of their wife's child. They're right some of the time, but most of the time, they're wrong: a good rule of thumb for players is that if your spymaster didn't tell you about the plot, your character is imagining things.
- Said trait returns in Crusader Kings II: any character that has it lowers his diplomacy, but increases his intrigue. In this case, however, however, it is one of the most useful traits in the game, since it also makes your character pretty much invincible against plots, which is quite useful in a world full of Ax-Crazy nobles.
- Teyrn Loghain Mac Tir, the Bad of The Good, the Bad, and the Evil ensemble in Dragon Age: Origins, is excessively paranoid of all things Orlesian, having spent his youth fighting a guerilla war against the Orlesian occupation of Ferelden. Unfortunately, this manifests itself in his utter distrust of the Orlesian chapter of the Grey Wardens a truly Impartial Purpose-Driven Faction as well, leaving Ferelden (which, for historical reasons, barely has any Warden presence of its own) defenseless when the Darkspawn attack.
- Freedom Planet has Neera Li, the distrustful advisor of the Royal Magister of Shang Tu. When Team Lilac and Torque attempt to explain to Magister the threat posed by Brevon, complete with providing the evidence in form of one of his machine fragments, Neera immediately accuses them of lying, basing it on the fact that Lilac and Carol are thieves who were aligned in the past with the Red Scarves, a group responsible for the Kingdom Stone's theft on Mayor Zao's behalf. She then deduces that they are criminals and spies who were bribed by Zao to come up with a cover-up story to justify the Stone's theft, which results in the Royal Magister locking the team in prison, with Torque and his evidence put into quarantine. Not only this results in Team Lilac losing hope in gaining Shang Tu and the Magister's trust, but they end up attempting to take the matter into their own hands, culminating in Torque's capture by Brevon, and Lilac's kidnapping and horrific Cold-Blooded Torture, also by Brevon.
- In Life Is Strange, we have David, Chloe's step-father and head of security at Blackwell. While he's Properly Paranoid in some respects (he even pulls a Big Damn Heroes in the timelines where Max and Chloe confide in him or he finds their notes), he goes about it in a very heavy-handed manner, suspecting and accusing completely innocent parties, which is one of the factors that leads to Kate's potentially successful suicide attempt at the end of episode 2.
- In Middle-earth: Shadow of War, there's a chance that the Overlord of a fortress you're besieging will capture your spy and publicly execute him before the showdown. Unfortunate for you, unless...
Allied Captain: Well, that was dramatic... and misguided, as we have no spy in this fortress!
- In Pathfinder: Wrath of the Righteous Prelate Hulrun sees hidden demon-worshippers in every mishap or disagreement, and his Third Crusade quickly devolved into a Witch Hunt. When the player meets him, as the city is actively being invaded by demons and the secret cultists are all coming into the streets armed to support them, he's focused on tracking down and executing a handful of worshippers of a benevolent goddess he wrongly blames for the attack. It's quite likely the player will be accompanied by someone he tried to burn at stake as a child, which he is completely unrepentant for.
- Until Dawn: If Emily gets bitten by the Wendigo, Ashley and Mike become convinced that she is a Zombie Infectee who poses a danger to the group and will try to force her out of the saferoom. Depending on the player's decision, Mike can even shoot and kill her. However the situation unfolds, Ashley will find a case study on Wendigos soon after, which confirms that their bites are not infectious at all and their panic was entirely unwarranted.
- This is the Fatal Flaw for Ironwood in RWBY, especially during Volumes 7 & 8, as the mere appearance of a chess piece crafted by the mastermind behind the Fall of Beacon is enough to trigger flashbacks to his failure to defend Beacon and conclude that an evacuation he was overseeing was exactly what the villains wanted to sneak on aboard. From there, he begins to make bad decision after bad decision to try and keep himself and Atlas safe, eventually driving every ally he has away from him and causing enough division to ensure that Atlas falls anyways. The worst part is that this was what the villains really wanted out of him.
- In The Order of the Stick, Girard Draketooth was one of the members of the Order of the Scribble, who journeyed through the world to seal the five rifts caused by the Snarl. After the Order split up due to differences between its members, he was certain that Soon Kim would soon come to check on Girard's gate despite their oath not to, unable to comprehend how a Lawful Good character thinks. Girard also didn't trust anyone who was not part of his family, which worked fine until they all became collateral damage of the familicide spell Vaarsuvius cast on the reanimated head of an ancient black dragon who was remotely related to Girard, leaving his gate completely undefended save for a few illusions.
- Schlock Mercenary: Discussed; Maxim 40 is "Not all good news is enemy action." The idea being, of course, that sometimes you do get lucky, and you can't constantly be looking for snakes in the grass. But since this is a story, it turns out to be enemy action anyway.
Mako: I'm a field agent, I'm not allowed to quote that one.
- Afterlife SMP: Near the start of her ninth episode, Enigma Lizzie hears Angel Scott breaking blocks near her hidden base. Believing he was there to "uncover the mystery" of her having undergone a FaceHeel Turn, she fixates her Deadly Gaze on him and accidentally murders him by staring at him for too long. For context, Scott was picking flowers at the time.
- Played seriously in Dream SMP. During his spiral in the Pogtopia arc, Wilbur was completely paranoid about everyone except Tommy either turning on him or dropping him once he's no longer useful. This carries across to after he dies and is brought Back from the Dead as well, where he talked to Phil about imagining him having a spatula put through his skull while building the burger van before Phil forced him to interact with Ranboo. His content creator counterpart eventually even confirms in a Reddit comment that his character "was suffering from intense paranoia and delusions".
- In Whateley Universe, Reverend Englund discovers that a student in the school named Sarah is actually a half-demon named Kellith, and becomes convinced she plans to Take Over the World. While normally, he'd be right since he's encountered all manner of otherworldly creatures that have done harm, in this instance, Sarah had undergone a HeelFace Turn and planned to spread love throughout the world. Unfortunately, Englund's delusions lead him to enlist the help of the Syndicate to eliminate her...which ends up causing a colossal amount of damage.
- Like the comics, this trope crops up in the DC Cartoons.
- General Newcastle on Superman: The Animated Series believes that Superman is evil just because he's an alien and nothing else. When he becomes a founding member of CADMUS and eventually retires, he still keeps a pistol with Kryptonite-laced bullets next to him at all times because he thinks Superman will eventually come and try to kill him (and never seems to consider that CADMUS might do it because He Knows Too Much...).
- The CADMUS plotline on Justice League Unlimited is also eventually revealed to be this: people who were concerned about superhumans going evil jumping the gun straight into Fantastic Racism, fascist tactics, inhuman weapon experiments, and attempted genocide not to mention other war crimes like launching a Kryptonite-laced nuke right at a still-evacuating island, thinking of all the innocent people as "acceptable casualties" as long as Superman (and Doomsday) died. The CADMUS example might possibly skirt the line between this and Properly Paranoid. On the one hand, the series goes to great lengths to imply that it is reasonable to be afraid of what uncontrolled superhumans could do, to the point of introducing an alternate universe League that went rogue just to prove the point. However, it is also frequently pointed out that CADMUS may have partially started the problem by doing things like creating Doomsday, attempting to kill or discredit the League, and attempting to create their own army of superhuman mooks some of whom were only children all before the League had done much to them.
- Amanda Waller, one of the founding members of CADMUS, ultimately has a HeelFace Turn, acknowledging she was wrong about the League and ruefully admits in the last season of Unlimited that she and her fellow CADMUS co-conspirator General Eiling (the one who launched the aforementioned nuke) are lucky not to be in prison. Eiling, on the other hand, doesn't learn his lesson and only gets worse, culminating with him injecting himself with a Super Soldier serum (a formula made by the Germans back in WWII, even) to become the Hulk wanna-be "the Shaggy Man" and wrecking half of a city trying to force the Justice League's big hitters (especially Superman) to come so he can try to kill them with his bare hands and get rid of "their threat to the citizens" for good to his satisfaction. It takes the population of said city coming to him and pointing out that he is the one who wrecked the city and the Leaguers he's pummeled so far (Badass Normal-types) have their support because they tried to stop him and are quite visibly the underdog in this situation to make Eiling stop, accept that he's the one in the wrong, and go away after warning that he will come back if the League screws up (and out of the show for the rest of its run).
- Avatar: The Last Airbender: After being betrayed by the people she thought she'd best terrified into loyalty, Azula becomes dangerously paranoid, seeing traitors everywhere and exiles bodyguards and servants left and right. In the end, she is left alone to fend for herself against Zuko and Katara, and is beaten.
- In Monsters at Work, when Tylor is assigned to M.I.F.T, Duncan immediately takes a dislike to him because he thinks that Tylor has his eye on Fritz's position, which Duncan is in line for. Despite Tylor constantly telling him that he doesn't want Fritz's job, let alone that it wasn't his idea to be a part of M.I.F.T in the first place, Duncan doesn't believe him. Even at the end of the first season when Tylor becomes a Jokester, Duncan still says he's watching him.
- Stork, of the Storm Hawks, has boxed and labelled contingency plans for many unlikely outcomes, such as brain worms or mind control. He's also extremely twitchy and constantly predicting the worst case scenario for everyone. The now-defunct Storm Hawks website reveals this is because his homeland of Terra Merb is constantly beset by natural disasters, though we never see it in the series proper.
- Plenty of historical dictators were very much paranoid. A random example is Josef Stalin, whose purges to protect himself crippled the Soviet Union's military, yet led him to trust Adolf Hitler on the basis of "I see myself in him and I would never do that", in the face of loads of evidence to the contrary. Another is Pol Pot, who was so afraid of "intellectuals" "contaminating" his dictatorship that he went as far as executing people solely because they wore glasses.
- In his memoirs, William Tecumseh Sherman identifies this as one of his flaws. When he was given a command early in the war, he was so concerned about Confederate movements that he sent alarming reports to his superiors. The government found the reports so exaggerated (based on the information they had from other sources) that it was feared he was suffering a nervous breakdown and he was temporarily taken off active duty. Ironically, Sherman felt so depressed he actually did suffer a mild breakdown. He got better once he returned to duty, and he alleviated his paranoia about enemy movements by making extensive use of scouts so he would always have an idea of where the enemy was.
- This is also why Sherman acknowledged Ulysses S. Grant as his superior in terms of warfare: where Sherman would allow himself to get crippled with doubt over enemy movement, Grant refused to allow his fears to override him and would carry on with his plans to the point the enemy had to respond to him instead.