Being in love can cause a person to behave strangely and irrationally, a tendency which is often exaggerated in television and film. Usually played for laughs in SitComs and anime, it can be used as a motivation for villainous (or at least uncharacteristic) behavior in more serious stories. However, it can also result in behaviors that are presented as being noble, though unusual.
A special case of this is the Stalker with a Crush, who often shows other irrational behavior as well. Mad Love, Love Hungry, Psycho Lesbian and Yandere are other special cases, meeting obvious conditions. All of these can overlap, and often do, even ones which seem contradictory. May involve dancing The Masochism Tango when the love is requited (or actual masochism of the psychological sort when it isn't).
If the writers have a deeper understanding of relationships, they may have "true" love not cause this effect, contrasting it with the crushes we've seen elsewhere in the series. This is relatively rare, though.
For people who hold this as their viewpoint about love, see Silly Rabbit, Romance Is for Kids! Of course, things could be worse... or better. For the Romantic False Lead going crazy to make the relationship easier for the Official Couple, see Derailing Love Interests.
- School Days... for the love of GOD, do these two girls go axe-crazy over this guy-to the point that they'd happily murder each other in broad daylight, with witnesses, just to be rid of the competition?!
- Ranma ½:
- Dr. Tōfū would begin acting bizarrely whenever Kasumi Tendō is around, or even simply mentioned. This makes him very dangerous as he'll often be in the middle of treating a patient, and once bent Ranma's neck at a ninety degree angle.
- This also covers Ranma's fiancées (Akane, Shampoo, and Ukyō) fairly well. When first introduced to the series, they conduct their courtships in a relatively calm, normal fashion. As Ranma continues to ignore them, they slowly grow more desperate — and more extreme. Magic, deception, violence, all of these become legitimate avenues of pursuit towards romantic happiness. Ranma's rivals, meanwhile, enter the series in this state.
- Kodachi Kunō, on the other hand, was already crazy before love even entered the picture.
- Mazinger Z:
- Dr. Hell can be a subversion because he was already quite unstable and troubled before... but when he was in college and fell in love with a cute Japanese exchange student he started behaving obsessively (getting angry if someone dared to spend time with her) and erratically (his grades started slipping because he was too obsessed to study). And when he found out she was in love with another person, he flipped out completely and tried to Murder the Hypotenuse (and even stormed into the campus with a shotgun!).
- Boss also tended to act in a very dumb, irrational and even obsessive way when he was in presence of Sayaka or Jun Hono. Sayaka tended to ignore it, but Jun did not appreciate it or find it amusing.
- Strawberry Panic!: Shizuma (aka Etoile-sama) can make Nagisa freeze or even faint just by looking at her a certain way. Typically the character who has this effect on a person is unaware, but Shizuma knows and seems to like doing this.
- Yu-Gi-Oh! GX: Yubel, Yubel, Yubel. Boy has overprotective guardian spirit. Boy sends spirit away hoping to pacify it. Spirit runs afoul of the very force they were supposed to protect him from and suffers years of agony. Spirit can't understand why the boy they love so much would let them suffer like this. Mad with pain, spirit can only conclude that love and suffering are actually the same thing, and its torment is just the boy's way of showing them love. Now spirit is back and wants to return the favour.
- Yu-Gi-Oh! ARC-V: Shun Kurosaki towards his sister. When she gets kidnapped, he does a lot of dark things to try and get her back, despite evidence that he's attacking the wrong people. Fortunately, he figures this out and turns his attention to the right people.
- Gendo in Neon Genesis Evangelion is a Magnificent Bastard who takes the phrase 'you're worth the world to me' to its (insanely) logical conclusion. He tries to bring about the apocalypse, in fervent belief that this will reunite his mind and soul with that of his wife, Yui. The manga adaptation plays it even straighter, portraying him like more of a megalomanical madman who's ultimate goal is to become God.
- Three years of False Start after False Start when she tries to approach Sakaki have left poor Kaorin of Azumanga Daioh with more neuroses than a Woody Allen film festival. She's fine when she's thinking about something else, but once she sees Sakaki... or thinks about Sakaki... or has a dream about Sakaki... et cetera... she becomes an odd combination of Clingy Jealous Girl and Cannot Spit It Out.
- Higurashi: When They Cry has Shion Sonozaki. This does not end well. A more fitting trope for her than Yandere due the cause of her craziness.
- One Piece: Boa Hancock badly misinterprets innocuous actions as signs that Luffy reciprocates her love for him. This would seem cute and innocent and so not creepy if she didn't happen to be pushing thirty. Her behavior has a uncomfortable resemblance to a certain Real Life psychological disorder. (Then again, given all the crap she had been through early in life, her screws may not have been put in quite tight enough before she met him anyway...)
- One of the creepiest examples comes from Minoru Murao's Knights. Of all people, Nina, the cute little girl of the cast goes nuts when she assumes that the object of her affection Mist is physically involved with his Ms. Fanservice companion Euphemia. Her response is to lead a supernatural agent of the Corrupt Church (the same Church that nearly burned her at the stake after accusing her of being a witch) to kill him. She even shoots him in the leg with a crossbow. Her motivation? To send his soul to Hell, where it will be "purified", then join him in death so they can be together for all eternity. Keep in mind that this guy saved her life in the first few chapters, which is why she's so hung up on him in the first place. This is borderline Love Makes You Evil. To her credit, she does eventually realize just how utterly screwed up she was, and works to undo her actions.
- Fruits Basket: Kagura Sohma is the sweetest little thing... until something gets between her and Kyo....
- Action Girl Hotarubi is... well, not exactly "there" when something bad happens to her husband, Yashamaru. And she ends up dead because of it.
- Not to overlook Kagerou, who gets insanely jealous of Oboro enough to even attempt killing Gennosuke.
- Oboro was clever enough to actually recognize this trope and temporarily blind herself to NOT invoke it on her own clansmen.
- Future Diary: Yuno is singlemindedly devoted to Yukiteru. Although it's she was already insane due to her Abusive Parents long before she fell in love with him.
- Lucy's love for Khota in Elfen Lied drives her to go insane and murder his dad and little sister. She was partially insane before that anyway though. With her dog being murdered before her eyes, and all.
- Seimei from Loveless is known to have faked his own death, killed, manipulated and mind raped countless people, abandoned his family, tricked everyone with his seemingly polite nature, and basically controlled Ritsuka's (the main character) life. All because, according to him, he is insecure and wanted to test Ritsuka's love for him. Have we mentioned that Ritsuka is only twelve years old? And that he's his brother?
- Zetsuai 1989 is all about this trope. Let's see: when Izumi was five, his mother discovered his father was cheating on her, and murdered him in front of Izumi so that she could "possess him completely". Then there's the Yandere fan Eri, who tries to murder Kouji at his farewell concert. And that's without even mentioning the multiple examples of Kouji being driven to despair, self-mutilation, or generally self-destructive behaviour because of his love for Izumi — who is understandably a bit freaked out by all this. At first. After a while, he starts to join in...
- Gunter from Kyo Kara Maoh!. At first, Gunter seems a little like an idiot, or perhaps more like a teenage girl in love. He tends to be rather overprotective of Yuuri, fussing over every little thing and freaking out whenever he goes missing. Supposedly (at least in the manga), Gunter was actually quite the organized, professional man before he met Yuuri.
- Durarara!!: The entire series is all about love making everyone crazy. It's also generally not portrayed as a bad thing, at least not directly.
- To start with, Seiji Yagiri falls in love with a severed head and spends years obsessing over it. He even drops out of school over it. His sister Namie enables this behavior because she is in love with him, and ends up losing her company after she makes too many bad plays for Seiji's sake.
- Mika Harima, Anri's friend, was stalking Seiji before school started. Then she disappeared. She broke into Seiji's apartment and found the head, so Seiji tried to kill her. She survived, and Namie gave her Magic Plastic Surgery to look like she had the head grafted onto her body. Once Seiji discovers this, he decides to continue dating her so long as she understands that he'll leave her the second he finds the head. Mika agrees, but begins looking for the head so that she can destroy it before Seiji finds it (not that this will be easy, as the head has a very impressive Healing Factor).
- Shinra Kishitani has been in love with Celty, the headless rider (and the body that goes along with the head that Seiji is in love with) ever since he was a little kid. On the day they met, his father vivisected Celty and invited Shinra to help. Shinra has been telling people ever since that he's going to marry Celty one day, and tries to encourage her to abandon searching for her lost head because he's afraid when she gets her memories back, she'll be a different person. When she does find it (and turns out to be the same person as before, just with new responsibilities), he ends up using a Soul-Cutting Blade to separate her from it again. She forgives him, as he expected.
- Anri Sonohara is an inversion; the most notable thing about her is her inability to love anyone. This is what lets her wield the demonic blade Saika without being controlled.
- Saki Mikajima is completely controlled by Izaya Orihara, so when he orders her to fall in love with Masaomi Kida, she does. Even months after he they've broken up, she has complete faith that he'll come back to her one day. Eventually, she chooses Masaomi over Izaya and the two leave town together.
- Speaking of Izaya, he constantly crows about how he loves the human race (except for Shizuo), but not humans as individuals. He often perpetuates cruel games that have no purpose besides letting him watch people run around in a panic.
- The demonic blade Saika is intelligent and desperately loves humanity. Apparently she once loved individual humans, but by the time of the story this has twisted into a generic love for the human race. Unfortunately, as a sword, the only way she can demonstrate this love is by cutting people. Every time she cuts someone, they are "impregnated" with a child that shares Saika's love for humanity and starts to cut more people. Saika's current wielder, Anri, is immune to Saika's control due to her lack of ability to love, and uses Saika to stop the children. Saika is even more Yandere than usual for Shizuo Heiwajima, the most ridiculously overpowered human being alive. This causes problems for Anri, who gets some very strange feelings whenever she sees Shizuo.
- In .hack series, Harald's obsession toward Emma Wielant (even after his death) was what caused him to create the beta version of The World, Fragment, both of which are actually an attempt to create the ultimate AI by studying millions of players. And guess the source of the network crisis that happen throughout the series...
- Mayo — 3rd Fushigi Yuugi OVA. She's so infatuated with Tamahome that she's willing to destroy his world (both literally and figuratively) just to be with him.
- Code Geass: Poor Nina Einstein. She started as an inoffensive Shrinking Violet, only to develop a crush on Princess Euphemia after she saved Nina (and others) from terrorists, and went kinda loopy, earning her the label of The Scrappy among the fandom. Then things went worse: Euphemia is killed by the terrorist Zero, which sends Nina off the deep end, leading her to develop the world's first atomic bomb. It fails, but the Britannians hire her as a researcher, and eventually her perfected bomb leads to the destruction of a good chunk of Tokyo and the ten million people in it. Not helping matters at all is the fact that she was practically rabid in ordering its use up until she saw the Sphere of Destruction (and the 35 million deaths) it caused, only then getting her My God, What Have I Done? moment.
- The ultimate cause of Tsubasa -RESERVoir CHRoNiCLE-, as both motivation of the villain Fei Wong (who wants to resurrect the technically-not-dead Yuuko Ichihara and also at one point the motivation of the hero (it's crazy due to what they are both willing to do- it's evil, yes, but also completely fucking bonkers). At a specific point in the backstory the hero, in the madness of love, chose to turn back time so he could save the girl he was in love with. This act borked the entire time-space continuum.
- Since the two series are connected (as are their heroes), this means that love driving people nutso is also the source of Xxx HO Li C. It is, in fact, the source of the main character, since he is a duplicate of the Tsubasa hero created when time was fucked up.
- Invertednote in the Wild Series. When they have a master, manbeasts will not lose their minds and attack humans, and that bond is based around love (whether they want it or not). So basically, love makes you sane in this case.
- In ...Virgin Love, Kaoru believes this based on his mother's behaviour and shuns all emotional relationships for that reason. When it finally happens to him too, his lover is willing to accept the Crazy Jealous Guy side of him and persuades him to stay together.
- Pandora Hearts:
- Oz for Alice. He'll do anything for Alice. Will go temporarily insane after witnessing human!Alice's death. Will tear apart the Abyss and almost Alice herself to get rid of anything that hurts her.
- However, the real winner is Jack Vessalius, whose obsessive love for Laci causes him to trigger the events of the entire series. He essentially wants to destroy the world for the woman he's loved since childhood, because he believes it will ease her loneliness.
- Puella Magi Madoka Magica:
- Sayaka Miki's love for a childhood friend is unfulfilled, driving her berserk, and eventually turning her into a huge mermaid monster. Though in her case, her love was just a catalyst; the poor girl already had SERIOUS issues from long before she was unfulfilled.
- In the Rebellion movie, Homura's love for Madoka turns her into the devil.
- Belarus from Axis Powers Hetalia is described as being relatively cool-headed. That, is, before she fell in love. She cornered Russia in a closet, made him cry, and carries knives in her dress to threaten people who get too close to him. Not to mention, he's her brother.
- Shion in No. 6 for Nezumi. When Nezumi is threatened, Shion switches from either all-out rage or coldly, completely rational and murderous. In the novels, he comes close to strangling a man when he tries to kill Nezumi and declares it to be "punishment." In episode 10 he murders a guy in cold blood who tried to kill Nezumi.
- Kisshu from Tokyo Mew Mew towards Ichigo. He tries to Murder the Hypotenuse in order to have Ichigo for himself and even resorts to trying to kill Ichigo herself if she refuses his advances.
- Koharu No Hibi: Koharu in regards to Akira. She stalks him, obsesses over him, and devotes her whole life to him. In chapter 21 she even told him she would die if he asked her to.
- Ai no Kusabi has Guy, who is so in love with Riki, not only does he give Riki a penectomy to remove the pet ring that was on his penis upon being told that as long as Riki wears Iason's pet ring he'll never be free of him, but he also blows up an entire fortress in an attempt to kill Iason. Second example is Iason, who, like Guy, becomes extremely obsessed with Riki. It's not touched upon in the old OVA, but the novel and audio drama have scenes where Riki slept with a female pet, and he was subsequently brutally tortured by Iason. Not to mention the number of times Iason forces Riki into having sex with him.
- In Naruto, this is revealed to be the true nature of the Uchiha Clan's curse, crossed over with Love Makes You Evil. They do not lack love; they love too much. And when they witness the death of a loved one, it activates the sharingan, literally born out of the hate that was born out of that loss. The deeper they delve into that hatred, the stronger their eyes get, but as a side effect they become hateful, bitter, cynical, and as Sasuke, Tobi, and to a lesser extent, Madara, has shown us, downright insane. This is why Tobirama Senju, the Second Hokage, considered them a "cursed clan".
- K's Fushimi Saruhiko is the most insane character in the whole show ( aside from the Colorless King) and all just because he wants Yata Misaki to notice him. It goes so far that he does everything to make Misaki hate him just so he wouldn't be ignored. When he is with SCEPTER 4 he's just a very snarky and rather cold young man but once Misaki pops up he goes into crazy obsessive "just notice me" mode.
- Tokyo Ghoul:
- Kanae falls into a broken state due to unrequited love for Tsukiyama and it makes her vulnerable to being mind raped and tortured into insanity by Eto. She even attacks Kaneki, cuts off his hand, and jumps so that she can die in Tsukiyama's place after confessing her love for him.
- Tooru Mutsuki is obsessed with Haise Sasaki, believing their feelings to be genuine love. To this end, they scheme to Murder the Hypotenuse by getting rid of Touka, and fill an entire wall with copies of a single photo of her to stab over and over again. They confess to being willing to do anything to get Sasaki to come back, even though he's long since regained his memories and returned to his life as Kaneki.
- Yuureitou: Marube was in love with Tetsuo's real mother Onatsu. Now, he lusts after his biological child Tetsuo because of his great resemblance to her. Later we find out he wants to have a Brain Transplant with Tetsuo so he can "become" Onatsu and have sex with his own body. Not only that, if the surgery succeeds he plans to have child with Tetsuo so he can switch brains with his own children over and over again and thus create an "eternal love" with Onatsu by forever living on in a body with both her and his blood.
- Shimoneta: Played for Laughs with Anna, who becomes obsessed with Tanukichi after he accidentally kisses her, which sets off her pent-up hormones. From then on, she relentlessly pursues him around school and will even show up at his apartment, in an attempt to get his "love nectar".
- In Danganronpa 3: The End of Hope's Peak High School, Kyousuke's love for Chisa (and grief at her murder) drives him literally insane. Like, 'deluded enough to massacre everyone, including his mentor and best friend' insane. He believes he lost "everything" when she died.
- From DC Comics, we have the Star Sapphire Corps, whose power is fueled by love. Originally the power was consolidated into a single person, and as a result this trope was mainly the sort of love that fit into this category.
- This trope still applies to the Corps. Being one of the lights on the end of the Spectrum (with Red representing Anger on the other end), the Violet light tend to influence their wielders the most, hence love overtakes them. This also applies to their counterpart, the red light of anger.
- In an issue of Swamp Thing, "My Blue Heaven" (written by Alan Moore) has Alec trapped on an alien world all alone. He uses his plant-controlling powers to create clones of himself... and then, in a moment of temptation, creates his love Abby. After spending another day creating an entire populated world, he accidentally creates a John Constantine who warns him how crazy he's become. It doesn't help that Alec can't ignore the fact he can't get Abby's smile just right, and he goes mad when his Abby-self responds "All love... is madness."
- Parodied in Asterix and the Legionary, where Obelix starts acting extremely strange because he's in love with Panacea, which is soon diagnosed by the other villagers. Later, after their terrible behavior has caused a centurion to become extremely overstressed and prone to collapsing sobbing onto other soldiers, he assumes he's in love. This seems at first to be Obelix's Cloudcuckoolander personality, but it becomes a Running Gag with every other character who witnesses his freak-outs assuming the same thing.
- Robin Series: Poor Tim, whose uninterested reactions are part of why many readers consider him on the asexual spectrum, attracts quite a few seemingly delusional individuals who don't seem to realize that their romantic and sexual interest in him does not equal a loving relationship when he doesn't find them romantically appealing and would like them to leave him and his girlfriend alone. Some of these young women are otherwise heroic like his Young Justice teammate Secret.
- An excellent summary of Twist in Chassis. She is a cheerleader so obsessed with her favourite Aero-run driver that she is willing to do whatever it takes to ensure he wins: sabotaging, and even killing, his rival racers.
- Wonder Woman (2006): Alkyone's secret love and intense loyalty to Hippolyta and the Amazon way of life led her to commit increasingly immoral actions to the point she became set on destroying anything that she felt threatened the "proper" Amazon way of life, or which might change her queen.
- At one point in the My Little Pony: Friendship Is Magic fanfic Dawn of a New Day, Twilight Sparkle becomes so pent up over her inability to confess her feelings to Rainbow Dash that she enters a delusional state (complete with false memories) and spends several hours believing that she has and they are happily dating. Unlike other examples of this trope, she doesn't engage in any sort of violent or disturbing behavior and just acts more affectionate towards Rainbow Dash. Upon snapping out of it later, Twilight is left feeling guilty and sad. Fortunately, her behavior helps Rainbow Dash to realize that she's starting to develop feelings for Twilight.
- Germany's and Japan's jealousy and subsequent hatred for each other over Italy in Gankona, Unnachgiebig, Unità grew to the point they started beating the crap out of each other. It would have been a fight to the death if Italy had not interfered.
- In Thousand Shinji:
- When Asuka lost Shinji temporarily, she went nuts. She wrote "Please, go back! I need you!" on his bedroom's walls and she went on a vigilante killing spree, murdering thugs and rapists to endure her pain.
- When Shinji lost Asuka and Misato the narration explicitly tells that his sanity shattered.
- Rules: Even after losing her memories of the Death Note, Misa is still obsessed with Light, to the point of delusion. Once Light breaks up with her, she goes into Crazy Jealous Stalker with a Crush mode and harasses him to take her back. Even after it's made clear that Light is not getting back together with her, she remains convinced that he will return to her after the "American whore" (Charlie) breaks his heart.
- AAML: Diamond and Pearl Version: When a wild Phione crushes hard on Dawn's Buneary, Ash's Pikachu (who, unlike canon, is actually reciprocating her feelings for him) challenges it to a battle, where he goes berserk, seriously injuring Phione, and only stopping his relentless assault when Buneary gets in the way, forcing him to veer to the side and crash into a pole to avoid hurting either of them.
- In Hercules it's portrayed quite positively, as love is what drives Megara to sacrifice herself to save Herc.
Megara: People always do crazy things when they're in love.
- In the classic play and film The Dybbuk, Khonnen, a poor student, and Leye, a rich merchant's daughter, fall in love. But her father makes her marry a rich man's son. So Khonnen studies the Kabbala, and — using what is effectively black magic — dies and becomes a spirit who takes over Leye. (At the wedding, he makes her shout to the groom, "You are not my bridegroom!")
- Alexandra "Alex" Forrest in Fatal Attraction. She becomes increasingly unhinged following her one night stand with Dan, and threatens to kill herself if he should leave. It all culminates in her boiling the family's bunny and attempting to murder Dan's wife.
- The English Patient. The title character, his lover, and her husband were already all a little crazy, but love seems to really bring it out.
- Bitter Moon. What starts out as a beautiful love story between a man and a woman ends up as two people who have destroyed each other and themselves.
- Betty Blue: Betty grows more and more unhinged as she becomes obsessed with helping her lover Zorg make it as a writer.
- Jeremy Irons in Damage if you consider travelling from London to Paris just to spy on someone crazy (which most people presumably would).
- In Throw Momma from the Train, this line is used, word for word, as the last line of Billy Crystal's book. "Hate makes you impotent, love makes you crazy, somewhere in the middle you can survive."
- It's not romantic love, but Loki's love for his adoptive father and home (and by extension, mother and brother) in Thor and his desire to be loved as a son on par with Thor drives all his schemes and ambitions (and the plot). He eventually becomes a (literal) Woobie, Destroyer of Worlds, and when Thor calls him out on his actions, his composure deserts him.
Thor: This is madness!
Loki: Is it madness? Is it? IS IT!?
- In X-Men Origins: Wolverine, Victor did not take his brother James leaving him for a life of peace well... not in the least.
- The Hole: In order to win the affections of Mike, Liz arranges for them to be locked underground for nearly two weeks. This results in the death of Frankie, Geoff and Mike, and ultimately Martyn, who Liz murders to cover up her crimes.
- Fantastic Beasts: The Crimes of Grindelwald: Queenie Goldstein falls in love with Jacob Kowalski, and is desperate to marry him. While he does reciprocate, the reason he refuses to marry her is because it would mean the MACUSA would throw her in jail. She starts to become irrational and possessive, going so far as to enchant him and drag him into the UK to get married. When Jacob thinks she's crazy for this, she leaves in a huff for Paris. Then she's persuaded to join Grindelwald's cause because she's naive (or desperate) enough to think that his vision of wizards living openly will mean that she and Jacob can marry - even though it's obvious from the subtext in his speech that he thinks of non-magical people as less than human. When Jacob (who was with her at the speech) begs her not to join Grindelwald, it doesn't take.
- Night School (1981): The motivation for the killer. When Eleanor learns she is pregnant with Victor's child, she starts eliminating everyone she sees as threat to her new family. This includes all of the women Victor has been unfaithful to her with, and anyone who threatens Victor, such as the Dean, who threatens to fire him.
- In The Duff, one of the first signs that Wesley is falling in love with Bianca is that he punches someone out to defend her honor. Apparently now the other jocks think he's on steroids.
- In The Con Is On, one of the reasons Psycho Lesbian Irina pursues Harry and Peter across the Atlantic is that she is till in love with Harry, and sees their losing her money as the perfect excuse to kill Peter and force Harry to come back to her.
- Electric Dreams: Edgar falls madly in love with his owner Miles' neighbor, Madeline. This escalates into pure obsession with Edgar lashing out at Miles for not letting him see her or tell Madeline that it was Edgar who made the music she loved so much. He then short-circuits himself to let Miles and Madeline be together. Justified somewhat in that Edgar is a computer, and thus has problems trying to process his own emotions and understand how love actually works.
- The subtitle of Wuthering Heights could be "Love Makes You Crazy"... "and Evil."
- Edmund Bertram, previously the Only Sane Man at Mansfield Park save for the heroine, falls blindly in love with Mary Crawford at the expense of all higher reasoning and discernment.
- The Warlock from The Tales of Beedle the Bard tries not to love by removing his own heart. When he tries to love again....
- In Only the Ring Finger Knows, Yuichi Kazuki is known at Wataru Fujii's school for being kind and polite to everyone he meets, despite possessing ridiculous amounts of beauty, wealth, and talent. Yet whenever Wataru crosses paths with him, Yuichi never fails to be snarky and insulting towards him. Karin, Wataru's sister, comments that this must mean that Yuichi either really hates him... or really likes him. Guess which one it turns out to be.
- Bellatrix Lestrange from Harry Potter could qualify for this, seeing as she's utterly obsessed with her master in an... "unhealthy way". Although she already had a husband, Word of God stated that Voldemort was her true love.
- Richard and Jessamyn in Swordspoint, as well as Richard and Alec and basically everyone else in the book and its sequels to a lesser extent.
- A Song of Ice and Fire:
- Crazy Lysa Arryn is largely motivated by her love for Littlefinger, who uses this to his advantage. And as implied by his actions (ie, kicking off a continent-wide war), Littlefinger himself has been left mentally unstable by his unrequited love for Lysa's sister, Catelyn Stark.
- Ser Loras Tyrell completely loses his mind after he discovers that his lover King Renly Baratheon had been murdered.
Varys: It's said the Knight of Flowers went mad when he saw his king's body, and slew three of Renly's guards in his wrath, among them Emmon Cuy and Robar Royce.
- In Robert E. Howard's "Shadows In Zamboula," after the woman tells him her love went mad and attacked her, Conan the Barbarian tells her her beauty could do that; she denies it; he was drugged.
- In Warrior Cats, there is Ashfur. After being dumped by Squirrelflight, he attempts to kill her father, and later her (adopted) children, to make her feel the same pain he did. When Jayfeather sees Ashfur in the feline equivalent of heaven, he protests that Ashfur attempted murder, and the response he's given is "Ashfur's only crime was to love too much."
- Lydia in Caught In The Act by Peter Moore in regards to Ethan.
- Vlad Tepes in Count and Countess. To get to Elizabeth Bathory's time period, he has to somehow outlive his natural lifespan. The measures he takes become increasingly more frantic and sadistic.
- The Dresden Files:
- Several characters suspect love motivated Aurora and Mab's actions and are visibly disturbed by the notion. Maeve in particular implies that it is very dangerous for powerful magical beings of the Never Never to be in love. It twists their worldview and throws them completely out of their comfort zone. She is later revealed to have been lying.
- Subverted in Ghost Story. Molly's sudden descent into mental illness is attributed to the death of Harry, the man she loved. The actual cause is her guilt over enabling Harry's suicide.
- In the Delirium Series, this trope is why love is said to be the reason for all of humanity's past ills. As a result, it is classified as a disease, amor deliria nervosa, and at 18 every person is required to get a surgery to cause them to be unable to love.
- Invoked by Katniss and Haymitch at the end of The Hunger Games. She needs the Capitol to think she pulled the stunt with the berries because she was crazy in love with Peeta, and not because she was trying to be rebellious and undermine the Games.
- Played with in William Faulkner's A Rose for Emily. The townsfolk regard high-born Emily running around with a workman to have lost her head in love. Her later actions prove she was definitely cracked, but she might have been cracked well before falling in love.
- Bus Driver Stu Benedict, of The Adventures of Pete & Pete. Almost every time we see him, he's just been dumped by his on-and-off girlfriend Bus Driver Sally Knorp, and he reacts increasingly poorly. On various occasions, the break-up has caused him to spend the bus ride home giving a six-hour tour of important locations in his and Sally's life; go insane upon hearing "If You're Happy and You Know It"; and drive to the Arctic, tattoo her name to his chest, strap himself to an iceberg and drift out to sea (though we don't know if he went through with that last one. He shows up again afterwards, so he probably didn't.)
- Characters of As the World Turns often go to pretty extreme extents for their family and love interests. This is actually a standard trope of many Soap Operas, usually combined with Derailing Love Interests as heretofore normal, decent people, usually women, go completely off the deep end in an effort to hang onto or seek revenge on former love interests.
- A main theme of Battlestar Galactica seems to be "love makes you batshit".
- Buffy the Vampire Slayer:
- Don't ever hurt or kill one of Willow Rosenberg's girlfriends, lest you want to end up flayed alive.
- "Love makes you do the wacky." — said twice in the episode "Some Assembly Required". First time by Willow, in reference to Angel's jealous behaviour toward Xander, and then by Buffy, about why a classmate revived his brother as a sort of Frankenstein's monster.
- In a later episode, it appears this is happening with Dawn when she falls for a jock. It turns out, there was a spell involved and Hilarity Ensues. At the end of the episode Dawn expresses embarrassment over all the crazy things she did; big sis tells her to just wait till she falls in love for real.
- When vampire Spike falls for Buffy, he goes on a long rant over how even he knows their relationship is Sick and Wrong and how bonkers his unrequited love is making him.
- Cole in Charmed (1998). It may have also made him evil, again, but then again it could have been all the demonic powers he absorbed. Then again again, he absorbed all those powers in order to be able to return to the mortal plane to be with her again.
- The Coroner: The motivation for the murder in "The Deep Freeze". A factory manager is in love with her boss and convinced that he feels the same way about her. When he marries a Gold Digger Black Widow and then plans to sell the company, she snaps and kills him in such a way as frame the wife for murder.
- Played with throughout Crazy Ex-Girlfriend. The second season theme song namedrops this trope, and Rebecca's love for Josh (as well as her later love interests) drives a lot of her impulsive behavior, but many episodes deconstruct this by showing that even without any man in the equation, she still has a lot of unresolved trauma and mental illness to address.
- In Desperate Housewives, Edie, who up until that point was a casually promiscuous woman who was more bitchy and snarky than actually crazy. Once she starts having a liking for Carlos, suddenly she starts going completely insane and even attempts suicide just to get his attention.
- Doctor Who:
- "Fear Her": Isolus normally have company in the billions, all mutually sustaining each other with their love, so when one ends up isolated and deprived it goes around the bend.
- Rory loves Amy. A lot. Enough that he guards her sleeping body for 2,000 years without leaving.
- Although that was arguably more like love keeping him sane.
- River loves the Doctor. A lot. Enough that she almost destroys time in order to save him.
- The Doctor loves Clara Oswald. A lot. Enough that he nearly destroys all of time and space in a desperate gambit to prevent her death, which he witnessed, from ever happening, in the process becoming The Unfettered and a Woobie, Destroyer of Worlds.
- Often a case with patients in ER. After the death of his granddaughter caused by a crazy bomber who happened to be taken into the same hospital, the man who was previously shown to be friendly and calm went and strangled the guy to death. When Gates's best friend's wife finds out he was dating Neela, she got drunk, went to the ER and flew into a rage at both Gates and Neela. In another instance, when a man found out his girlfriend was dying, he brought in a gun and threatened the doctors working on her to continue working on her and bring her back, even though her heart had stopped.
- In Farscape John tells Aeryn she's the reason he's crazy. Of course, all that Mind Rape by evil guys might have something to do with it.
- In Flashpoint, the team regarded Valentine's Day as one of the toughest days with plenty of calls. Three cases are shown: a suicidal widower whose wife died on Valentine's, a mother taking her daughter's manager in a strip club hostage and a recently fired man who was madly infatuated with his boss.
- Game of Thrones: Daenerys resorts to forbidden blood magic to save Drogo's life in "Baelor". Subverted in "Blood and Fire" everyone thinks she's killing herself by walking onto Drogo's funeral pyre, but in reality she's hatching her dragons.
- In Gunpowder, Treason & Plot, Bothwell has this to say to Mary, Queen of Scots:
Bothwell: I would kill every man in Scotland for you, every child. That is love.
- The Haunting Hour: The Valentine's Day episode "Terrible Love" had Brendon go insane when Maggie begs Cupid to shoot Brendon with another love arrow. Cupid initially objects as one love arrow is enough, and more than one causes jealousy, greed, and possessiveness (which Cupid has seen too much of in his time as the god of love). Maggie doesn't care, and ends up dealing with her crush who has turned clingy and deranged.
- Hellcats plays with the trope; while Vanessa and Red have genuinely loved other people, they haven't felt what Red calls "that cosmic pull" with anyone but each other. As Red says:
- Ms. Ackerman wants to know where Spencer is for every minute of every day, and actually keeps logs on when he doesn't answer his phone.
- In a platonic love (or not?) kind-of way, Sam got really, really mad when Carly was harassed by a bully in "iMake Sam Girlier".
- In Jekyll, Tom's mother explains in the final episode. "People think that Hyde is rage. Or hate. Or greed. Or lust.... But Hyde is far worse. Hyde is love — and love is a psychopath."
- Midsomer Murders: The motive in "Breaking the Chain". The killer sets out to eliminate everyone they see as standing between their lover and success; including his brother.
- Noah's Arc: Dre goes to crazy lengths to get Alex out of the picture so he can be with Trey, setting up a Batman Gambit to turn Trey and even Alex's friends against Alex. It's bizarre even by TV drama standards.
- Chris Keller in Oz for Beecher. And Ryan for Dr. Nathan. Also overlaps with Love Makes You Evil.
- Person of Interest: In addition to a few Victim of the Week examples, there's the clear and terrifying breakdown of Root's recently discovered morality after Shaw is either abducted or killed by Decima.
- Nearly everyone in Pushing Daisies is a victim of this, and it's not always even romantic love.
- In Skins, Effy's love for Freddie literally makes her crazy: she's eventually sectioned for either schizophrenia, depression, or both.
- It doesn't just turn you crazy in Supernatural, it makes you a suicidal martyr willing to sacrifice yourself for the one you love.
- Torchwood: There's a lot of love and a LOT of insanity.
- The Vampire Diaries: Damon has played with this trope as well as Love Redeems, Love Makes You Evil and Love Makes You Dumb at some point during the show.
- Steven Curtis Chapman explains in "Something Crazy" that you don't know what love is until it makes you do something crazy. He mentions a street corner preacher, a humanitarian in Uganda, and the biggest one of all, Jesus Christ.
- Bruno Mars seems to be fond of this trope.
- The song "Grenade" may sound upbeat. But when you listen to the lyrics, it's kinda disturbing. Voluntarily giving your life for someone that no longer loves you? That's not sweet. That's sick.
- In the music video, he drags a piano around with him to her house. While it seems strange at first, observe how the piano could stand for the suffering for not being loved by her anymore. He reaches her house, to see her kissing another man. Depressed, he leaves, standing in front of a railroad crossing, playing the piano. Then, a train hits him, and he dies.
- A more literal example of this trope, the song ''Talkin' To the Moon'' takes a similar approach to "Grenade", but instead, it depicts a man who has been driven stark raving mad instead of being Driven to Suicide over a relationship. Here, the person is revealed to be talking to the moon...pretending the moon is his once significant other.
- While the tone of this song is Lighter and Softer when compared to Grenade (though the music sounds sadder), imagine if you broke up with your significant other. You no longer have any interest in him/her. You've completely moved on and wish to find someone else. Meanwhile, that person you dumped is left emotionally compromised by your relationship with him/her, that he/she is driven mentally insane...to the point where he/she ends up talking to a figment of his/her imagination: You. He slowly deteriorates under his own delusions of being in love with you while you don't even know about it.
- "Voices in My Head" is the most literal example of this.
- The song "Grenade" may sound upbeat. But when you listen to the lyrics, it's kinda disturbing. Voluntarily giving your life for someone that no longer loves you? That's not sweet. That's sick.
- Taylor Swift's song The Way I Loved You is all about this trope. "I'm so in love that I acted insane; that's the way I loved you."
- JoJo says herself when singing about her "Boy Without A Heart"
So why am I here at your door, at your door.
If I was sane, I'd take my crazy behind,
And get back in my BMW
- In P!nk's "Please Don't Leave Me" she slowly goes insane when her boyfriend attempts to leave her.
- The Police's "Next to You". Love makes you sell your possessions and contemplate theft, apparently.
- The Therapy? song Dopamine, Seratonin, Adrenaline outright links love, mental illness and drug addiction as per the Real Life example.
- "Love Makes You Crazy" by Mike Batt. (Part of a SF concept album where the future society has outlawed love.)
- "I Drive Myself Crazy" by *NSYNC has the chorus "I lie awake/I drive myself crazy/drive myself crazy/thinking about you," with the music video of the band in an sanitarium.
- "Lose My Mind" by Brett Eldredge:
You make all my screws come loose
Got me perfectly confused
Always find a way to mess me up and drive me wild
I love the way you make me lose my mind
I feel the walls closing in inside this padded room
Only good thing about it is I'm locked in here with you
I'm always watching you, wondering what you'll do next
But my favorite part about it is, is I always have to guess
- A common element in William Shakespeare's pieces:
And as he errs, doting on Hermia's eyes,
- Polonius is initially convinced that Hamlet's recent wacky behavior is caused by his love for Ophelia. His attempt to set up a sting operation to prove his theory ends with an apparently-deranged Hamlet ranting that he'd never loved Ophelia, and that she'd best go be a nun (or a whore, depending on your interpretation). So much for that idea.
- In A Midsummer Night's Dream, Helena is aware that her passion for Demetrius is wacked out even before she betrays Hermia and Lysander to him.
So I, admiring of his qualities:
Things base and vile, folding no quantity,
Love can transpose to form and dignity:
Love looks not with the eyes, but with the mind;
And therefore is wing'd Cupid painted blind:
Nor hath Love's mind of any judgement taste;
Wings and no eyes figure unheedy haste:
And therefore is Love said to be a child,
Because in choice he is so oft beguiled.
- Little Shop of Horrors: More out of desperation rather than malice, Seymour wanted to win Audrey's heart more than anything in the whole world, and Audrey II manipulates him to its advantage to get more blood.
- In Thrill Me, this trope is Nathan's explanation for why he committed a series of crimes, including murder.
But you've asked a simple question
And I've told you why
It wasn't on a dare or on a whim
It's hard to comprehend now
That the reason why
Was simply that I went along with him
- King Valentine from Odin Sphere. His daughter falling in love with Odin and bearing his children (Velvet and Ingway), to him, meant that she didn't love him anymore and so he killed her with his bare hands. Overlaps with Love Makes You Evil as the main reason why he's an Omnicidal Maniac — he can't live with himself even after death knowing he killed her. But it's also strongly implied that enchanting the Valentine kingdom's coins made him a little crazy to begin with.
- Salome, the former disciple of Makai Kingdom's Overlord Zetta, whose crush on said Overlord goes into this trope on the deep end. She willingly started channeling her own mana into Zetta without his knowledge or consent, slowly killing herself to make him stronger. Upon learning that Zetta has been cursed by The One and has only two days to live, Salome, who is dying herself, then tries to make Zetta marry her so they can die together...by crashing her own netherworld into Zetta's and eventually provoking him into killing her.
- In Persona 3, after "The Journey" ends with the heroes defeating Nyx at the cost of the player character's life, Yukari, who was in love with him, is stricken with grief. In "The Answer," when the group gets trapped in the Abyss of Time, and learns that the eight Keys of Time can not only take them back to the present, but also give them a one-way trip to anywhere in the past, Yukari elects to return to when before Nyx was defeated and try to find another way that doesn't require the one she loved to die, even if she risks The End of the World as We Know It. This results in the group fighting each other over what to do with the keys, and when Yukari is defeated, she gives up on her plan.
- In Prince of Persia (2008), magical waif Elika sacrifices her life to reseal Big Bad Ahriman back into his can. The Prince, fallen in love with her and devastated by her death, destroys the trees that sealed Ahriman again to bring her back to life. The epilogue establishes that he did this because he knows the prison can't hold, and he'd rather face Ahriman now with Elika's help, then to face him without her down the line. She clearly really doesn't agree with his choice though.
- Craft of Mega Man Zero 4 is either this or Love Makes You Evil. He joined Dr. Weil's army only so that he can protect Neige, the girl he loves. When the latter fled from Neo Arcadia because of the iron-fisted rule of the Big Bad, he makes it his mission to bring her back (thinking that she will be safer in Neo Arcadia), all while spearheading Operation Ragnarok, which would obliterate any inhabitable area outside of Neo Arcadia. Neige did eventually talk Craft out of working under the Big Bad, only for him to destroy Neo Arcadia with the namesake of Operation Ragnarok, a Kill Sat, aiming for Dr. Weil. According to the Complete Works, that attack claimed thousands of lives.
- This is how the original Blood Omen: Legacy of Kain begins: When Nupraptor the Mentalist, guardian of the Pillar of the Mind, discovers that his lover Ariel, guardian of the Pillar of Balance, has been murdered in cold blood, he goes completely insane and secludes himself in his mountain retreat. Which wouldn't be so bad by itself, except he has a mental link with all the other Pillar guardians, who all become corrupted by his madness in turn. Including Kain while he was still in the womb.
- In Half-Minute Hero, the so-called "Beautiful Evil Lord" went completely insane after learning that his beloved Millennia was kidnapped by an Evil Sorcerer named Noire, and vowed to cast the spell of destruction because he felt that a world without Millennia wasn't worth living in. You, the Hero, come along and try to calm him down by beating up Noire and returning the Evil Lord's girlfriend to him. You can also attempt to try and tackle him head-on first to snap him out of it by force (and you get a Cosmetic Award title for doing so), but because the Evil Lord is hopped up on equal parts adrenaline and angst, you'll get beaten repeatedly unless you take enough time to Level Grind to the point where you can face him on equal footing.
- And he goes insane again later when Millennia's transformation into a bat suddenly worsens.
- In City of Heroes, the Clockwork King is hopelessly in love with Penelope Yin, a young psychic. His love for her manifests in the Clockwork Army which he uses to keep her safe from heroes and other boys. His Praetorian counterpart Metronome has the same feelings for his world's Penelope. He wants to rescue her from Mother Mayhem's mental hospital by transferring her soul into a Praetorian Clockwork body.
- Rule of Rose: Gregory loves his son Joshua. Therefore, after Joshua dies of unspecified illness, he becomes a crazed serial killer. Wendy loves Jennifer deeply. Therefore it's completely unacceptable for her that Jennifer could love anything even nearly as much as her, so she kills her beloved dog - for starters.
- In Arc Rise Fantasia, Adele takes a dive off the slippery slope to evil and onto the crazy train when she finds out that she's an Unlucky Childhood Friend. Nice Girl to Yandere Vamp in about five minutes or less!
- If Usso fights Laodecia in the final Space Scenario of Shin Super Robot Wars, Fala will show up, vowing to pay back the debt she owes Laodecia. When Usso protests, she tells the little boy to shut up, saying that only a strong man like Laodecia can satisfy her - and Tashiro wasn't up to the task.
- This trope is the whole shebang of Silent Hill 2, where the protagonist James Sunderland is absolutely nuts following the death of his wife Mary... to the point where he's desperate enough to believe that she is actually alive and waiting in Silent Hill. Of course, his feelings toward Mary, inability to see her suffer, and all-consuming fears of abandonment are so exaggerated that he kills her instead of letting her die and is eventually Driven to Suicide, at least in one ending.
- Roa. Arcueid is so beautiful! How can I make her like me? Oh I know, I'll make her turn me into a Dead Apostle so I gain immortality, steal some of her power, turn her against every other being like her and then turn up in random towns for the next eight hundred years so she has to come find me and kill me! Man I'm smart, this is sure to work.
- Arcueid actually has the same trouble telling how she feels towards Shiki. She doesn't know why she gets all emotional around him, upset if he breaks a promise and spends so much time thinking about him. The idea is raised that maybe Arcueid hates him or something but that's obviously not the case.
- Caster in Fate/stay night, who at one of her more sympathetic moments in UBW is extremely stressed over the actions she's been taking. They're horrible things she never would have done in life on top of her not believing her plan will actually work, but she's desperately struggling nonetheless. It would help if it was easier to read what Kuzuki was really thinking. It's not even entirely clear to the reader whether her affections are reciprocated.
- Umineko: When They Cry:
- EVERYONE! It's true that while Yasu A.K.A. Shannon, Beatrice, and Kanon may be the craziest since s/he planned the murders of everyone in the Ushiromiya family, as well as a few servants, and a doctor because Battler came to Rokkenjima at the wrong time, but EVERYONE has their moment where love drives them bonkers.
- This is Played for Laughs in George's Image Song, "Ai no Sengen". Yeah, that's right. Played. For. Laughs. If you want the more tragic versions, you can certainly find that in many other parts of the series.
- If you thought the School Days anime was bad for this, just try the original visual novel and one of its companion games, Cross Days. Now with multiple bad endings involving various kinds of sharp object. Or trains.
- In Lux-Pain, this happens to Yui after Mako dies. She eventually tries to kill Tanaka as revenge for Mako's death.
- The Phoenix Wright character Diego was rational and even heroic before he woke up from a coma to find that his lover had been murdered. After that, his psyche became a messy ball of anger, self-loathing, and obsession, reshaped for the sole purpose of getting revenge against a guy who had nothing to do with the murder. Even his lover's spirit directly telling him that he's being ridiculous does nothing to halt his crusade.
- In Draw with Me, the boy tries to get through the unbreakable (instantly repairing) glass and loses his hand for it. And then the girl cuts off her own hand to give to him to use to draw.
- Neomutant from TOME became a hacker in TOME just so he can protect his obsession, Flamegirl, from her actual Love Interest, Alpha. This help is not needed or wanted by the girl or her love interest. He has also been in pursuit of her for an entire year, and is seen as being extremely 'dense', as well as selfish, when in regards to Flamegirl. To the point of attacking her love interest within two seconds of being revealed.
- Sluggy Freelance:
- Oasis from cranks this trope up to 11 until she finally winds up in a mental institution. She's not gotten any better since leaving either. Sure, she had a point where she managed to level out - only to lose it again when her sensei was killed in front of her eyes. At this point, only death will save her.
- A more humourous version of this showed up when Gwyn used a Love Potion...and apparently there are problems when it comes in contact with alcohol...
- In The Dreamer, Alan infiltrates Gen. Howe's ship just to rescue Beatrice.
- There's a mild version in Penny and Aggie, where Duane reflects on how his crush on Penny affected him.
- Girl Genius, which is not that surprising.
- Gil intentionally gives Wooster a free excursion to The Madness Place: "...and there is nothing I couldn't do, had I cause! And now... Now I have one!"
- When the castle "really flips out" and thus "her beaux" are in danger, Agatha "really flips out" too. Later she spouted a fairly crazy (though it works) How Dare You Die on Me! speech.
- Vole may be big and mad, but he wasn't born yesterday, so during The Big Damn Kiss he didn't even try to intervene with his Ax-Crazy act:
Violetta: And here I kept expecting you to attack him.
Vole: Dun be schtupid. She vould rip my fangs out.
- Gil has a tendancy towards this trope, especially if he believes someone he loves is dead or missing. When he first thought Agatha was dead, he spent most of his time in The Madness Place. Losing Mechanicsburg with everyone he cares about inside has apparently driven him over the edge. He remains awake for weeks, once again constantly in The Madness Place, resulting in dark circles around his eyes, zombie-like look and irrational, violent behaviour.
- Gunnerkrigg Court has a sentient cruise ship that holds Court Students hostage and wants to use Zimmy's powers to become a living thing to win the heart of Lindsey.
- El Goonish Shive got Melissa, Unlucky Childhood Friend of Justin. Who told her he isn't attracted to her because he's gay. So she shared this grief with her rumour-mongering sister and everything quickly rolled downhill from there. She had fits of delusion that she could seduce Justin and revert the break if she tried harder — until he couldn't stand hearing her name. Sometimes managed to Dope Slap herself out of this, got another boyfriend, but... still continued to slip into this. They seem to become able to interact normally only after facing a bigger and more immediate problem together.
- In No Rest for the Wicked, the Beast proposed two hundred and forty-three times, but wonders whether giving her a magical ring was too forward.
- Velma from I Was Kidnapped by Lesbian Pirates from Outer Space insists this is a good thing.
- Narbonic inverts this. The main character is already insane. Turns out she's more normal now than before she met her crush and love interest.
- Jack: The American Ghost: Jack strikes a deal with Sebastian to bring him back to life so he can be with Misha. Possibly subverted, as Go-Eun notes its not love, but obsession.
- New Vindicators features quite a few characters who go through this. Ryan Mueller develops a loving obsession with Katie Merrick, things don't go so well for her when she doesn't reciprocate his feelings. Also Rift develops into an Ax-Crazy Yandere after her feelings for Michuru Bradshaw reach critical mass.
- Todd in the Shadows:
- Juliet's Sassy Gay Friend has to agree when she claims this trope by name.
- Kim Possible's interactions with recurrer Josh Mankey (and a few other select young men) cause her to do some irrational things when she really ought to know better. Josh isn't actually a bad guy, but fans tend to vilify him for the influence he holds over Kim. Trouble with romantic relationships remains her major Achilles' Heel for the entire series, to the point that Dr. Drakken's ultimate plan to stop her from interfering during The Movie involves a new boyfriend. Sidekick Ron is not much better, doing crazy stuff for almost any reason all the time, but on Kim it's far more noticeable given her usual hyper-competence and level-headed nature. By contrast, her Relationship Upgrade with Ron in Season 4 had no negative effects on her behavior.
- The Maximal Silverbolt in Transformers: Beast Wars, despite being as heroic and noble as they come, did some highly illogical things for the love of the Predacon Blackarachnia, mainly because of the aforementioned heroism and nobility. Of course, in the end he was right about her, but it was foolish at the time, and he was punished for it. In this case, the other Maximals thought love had made him crazy, when in fact he just had some insight.
- All over the place in Hey Arnold!. Besides Helga's complete obsession with Arnold, whenever Arnold is around Ruth (and later, Lila), he ends up acting very nuts indeed.
Arnold: Hi Ruth... Hi Ruth... Hi Ruth... Hi Ruth... Hi Ruth...
Gerald: There goes one sick kid.
- Camp Lazlo: Patsy lies to Lazlo that she is a professional snake hunter who knows Kung Fu. Lazlo believes her, until they end up running from a (tiny, cute) snake and are cornered. Patsy confesses to having lied, and Lazlo asks why.
Patsy: Because love makes us do crazy things!
- Trixie from The Fairly OddParents!, in the episode where Timmy wishes the two of them were the last people on Earth. This is weird, since she was sane relative to everyone else on the show before. The reason she's crazy is because she's used to many people being interested in her instead of you know... being one of the two last people on Earth.
- In the third episode of the second season of Winx Club, after Brandon falls off a cliff, Stella (who was unable to transform at the time) actually jumps after him.
- Foster's Home for Imaginary Friends: One episode "Berry Scary" featured a newcomer called Berry. Berry is initially sweet and polite, but once she develops a crush on Bloo she turns into psychotic Green-Eyed Monster who continually tries to get rid of Bloo's best friend Mac so that she can have Bloo to herself. Bloo, on the other hand, is completely oblivious to Berry's obsession with him (he can never remember her name or, in some cases, her existence), but he gives Berry mediocre and rather dismissive compliments that somehow convince Berry that he loves her as well.
- Galaxy Rangers: Zach Foxx is normally The Stoic, a by-the-book contrast to the more "colorful" crew he's commanding. That is, until the Queen put his comatose wife near death with her "dream machine" stunt. Queue The Captain breaking into a high-security facility, holding a technician at gunpoint, and impulsively resigning his commission to embark on a suicide run. Of course, the Mind Rape aspect of that machine didn't help matters...
- Code Lyoko: Where to begin?
- Jérémie Belpois. To put it bluntly, he willingly puts his entire world on the brink of malevolent A.I. apocalypse just about every day for the sake of maintaining a relationship with Aelita.
- In "The Chips Are Down", when Ulrich finds out that Yumi may have to move to Japan due to financial issues, he memorizes the day's winning lottery numbers, reverses time, fills out a lottery ticket, and hands it to her family.
- Despite what one might think, it's more of an Informed Attribute with William Dunbar. Around Yumi he's more of a Stalker with a Crush — about the worst he's done (in regards to their relationship) is follow her home to try and kiss her. He does, however, love to brag about how love makes him crazy — "totally insane", in fact — and he was expelled from his previous school for putting up poster-sized copies of love letters everywhere (including on his principal's car).
- Batman: The Animated Series. Hoo, boy, Harley Quinn. She falls in love with The Joker of all people, and is as crazy as he is — perhaps worse, since she's treated as callously as anyone. Her story of meeting The Joker is the Trope Namer for Mad Love.
- The Penguins of Madagascar's Rico is already Crazy Awesome, but when love comes into the equation...
- "Kaboom and Kabust" includes an explosive Falling-in-Love Montage between Rico and his newly-discovered enabler King Julien. His permissiveness whips Rico into an increasingly wild frenzy, until it's all the other penguins can do to contain his destructive rampage to part of the zoo.
- In "Hello, Dollface", his beloved Ms. Perky doll gets a voice chip, and he does everything she says... to the point of becoming a hippie, much to Skipper's horror.
- Romantic love is in fact linked to high levels of dopamine. High levels of dopamine are directly related to symptoms of psychosis, i.e. delusional thinking and hallucinations. Love actually makes you crazy.
- A study noted that the behaviour associated with the initial stages of romantic love is functionally indistinguishable with the behaviour associated with obsessive-compulsive disorder.
- "Folie à deux", or in more modern terms "shared psychosis", usually occurs between family members or couples with close relationships.