Not every character who has been Driven to Suicide does it on an impulse. Often it's a premeditated decision and oftentimes they start behaving differently prior to the suicide attempt. Researching and talking about suicide and/or death a lot is a pretty obvious-seeming sign, though other signs may be more subtle. They might go around talking to loved ones or they might start giving away their belongings, as a way of telling them goodbye. Alternatively, suicidal people may withdraw from others physically and emotionally. Giving a Despair Speech or simply alluding to a loss of hope is common. Abrupt personality changes are also frequently present; for example, they might be either unusually somber or, after a period of depression, might be unusually energetic and content. Engaging in risky behavior such as dangerous driving, taking drugs, drinking to excess, unsafe sex, and so forth can be a sign too. Another physical sign is no longer taking care of one's appearance, such as not bathing/showering, not washing their hair, unkempt clothing, and so on (especially if they usually take pride in their appearance). Writing or recording a suicide note is often one of the last steps, though not in all cases.
There is Truth in Television in this trope. A common suicide prevention tip is to look for several signs that someone might attempt.
Secretly Dying characters also sometimes display the same characteristics as suicidal characters. If a character behaves this way and isn't suicidal, then they're often Mistaken for Suicidal. If other characters notice this behavior, they might put the character on Suicide Watch. Failing to notice the signs can result in characters feeling guilty, believing they could've prevented a tragic outcome. If characters do become aware of the signs, they may end up Talking Down the Suicidal.
- Fukiko from Dear Brother gives away an important belonging, a doll, as foreshadowing of her suicide.
- Days of Flight in Haibane Renmei are treated similarly to someone suddenly dying or someone committing suicide. Reki almost failing to achieve her Day of Flight in the final episode is treated especially so. She says her "goodbyes" to everyone, detaches herself from her friends, and packs up all her belongings. There's also the scene, right before she asks asks Rakka for help, where a younger version of herself stands in front of imaginary railroad tracks. The series ends with her realizing that You Are Not Alone, which allows her to break out of her Circle of Sin and take her Day of Flight.
- In The Summer You Were There, Shizuku, convinced that she can do nothing but hurt others, completes her "first and last story," deletes it from the internet and prepares to throw out the manuscript before killing herself. However, her classmate Kaori picks up the manuscript, reads it and takes steps to ensure Shizuku does not kill herself.
- Your Lie in April: Kaori is Secretly Dying and displays some signs, such as asking Kousei if he wants to commit double suicide (using a book quote). It's never specified how serious she is but it doesn't matter much as she dies only a few weeks afterwards.
- One issue of The Intimates focuses on Dead Kid Fred, a Robin expy who is stuck as a zombie as a result of Comic Book Death. Throughout the issue, he shows signs of being suicidal, but everyone ignores him until he tries to burn himself to death.
- In The Order (2007), Becky Ryan was initially kept off the team because her background check revealed a string of self-destructive behaviors, including drug abuse and eating disorders, but she ended up making the cut after half of the initial team was kicked out for public drinking. After she pulls a very public attempt at a Heroic Sacrifice on her first mission, Henry pulls her aside and asks her point-blank if she was trying to kill herself.
- Played with in an issue of Runaways (Rainbow Rowell) that sees Victor suffering from constant, worsening flashbacks to the time he killed his nephew. At the end of the issue, he's seen drawing a bath and tearing his own head off of its makeshift body and throwing it into the tub, which would seem like a suicide attempt, given that he's a cyborg. The next issue reveals that he was actually regenerating his original body.
- In the Animal Crossing Dark Fic one-shot Destroy Me, Please, the unnamed protagonist sells their belongings, sends their more valuable family belongings to their parents, and sells their home because they're "moving away". Their ever-vigilant secretary Isabelle notices the signs and doesn't completely believe them when they say they aren't suicidal. Isabelle later visits the protagonist and interrupts their suicide attempt.
- The End of the World: An ambiguous example. Right before going on the hiking trip where he somehow fell off a cliff, Albinus Drake gave his victory Tour plaques to Brutus, and his record collection to Cinnamon Calabry (a minor District 2 victor). Drake had been depressed about the Games in the months before his death. Brutus seems to think it was suicide (and blames Haymitch for it), while Mags speculates that Drake was murdered by the Capitol for his Rebel sympathies, in which case his giving away stuff was because he expected to be murdered soon.
- moral of the story (Nyame): The first scene shows the aftermath of Oliver and Laurel's confrontation in the hallway, Laurel's decision to kill herself, and her typing out her suicide note explaining her actions. It ends with her grabbing a bottle of pills, preparing herself to do the deed. The actual death itself isn't permanent due to the Lazarus Pit, but Laurel's decision nonetheless causes reverberations throughout the plot.
- In My Immortal, an infamous Harry Potter fanfiction, Ebony can apparently pick up on Draco Malfoy running "in a suicidal way".
- Pokemon Light AU: Gloria's already volatile personality took a turn for the worst a few months before her suicide. She began isolating herself and pushing her loved ones away. Her last few voicemails to Hop, however, were soft and heartbroken.
- After being sent back in time, Gloria bemoans in Anachronism that she missed the, now obvious, signs that Sonia was depressed. Sonia's frequent Heroic Self-Deprecation isn't as digestible after learning what happens to her.
- In RWBY: Scars, Weiss has spent the last several weeks more-or-less isolated in her room. She rarely gets dressed and barely eats. Right before her suicide attempt, she decides to talk to her mother, brother, and favorite butler. This unusual behavior actually saves Weiss' life. Her normally distant mother decides to check up on her for once and finds her bleeding out on her bedroom floor. Willow's quick thinking leads to an Interrupted Suicide, which eventually leads to a Happily Failed Suicide.
- Iron Man 2: Tony Stark begins to subtly go through the warning signs of suicide, he engages in risky behavior (untrained participation as a race car driver and getting drunk while operating heavy machinery — his suit), he's gregarious in front of the camera, but having trouble speaking to his friends, and he starts giving away personal possessions (donating his entire modern art collection to a Scouting program, giving his company to Pepper, and allowing Rhodes to take an earlier model suit in a destructive combat in his own home). Played with in that he's not actually suicidal; his medical equipment which he depends on for survival is also killing him, causing the same death-seeking and "last will" behaviors common to people with suicidal thoughts. The first one to notice in the movie is Nick Fury and they talk about it in a remote diner, starting him down the path to curing himself.
- The Belgariad: In the prequel novel Belgarath the Sorcerer, Belsambar falls into despondency in the years after the Cracking of the World and the wartime atrocities he'd witnessed. One evening, he talks to Belgarath about his lack of hope for the future, wishes Belgarath "goodbye" instead of "goodnight", goes home, and wills himself out of existence later that night.
- Les Misérables: Inspector Javert stands over a dangerous stretch of the River Seine while he struggles with the impossible contradiction of owing his life to a criminal he'd sworn to arrest. He then goes to the nearest station-house, writes a few suggestions to improve the police service, returns to the Seine, and throws himself in.
- The Wolf Den Trilogy: Cressa drinks her savings and starts looking haggard in the months leading up to her suicide. Her final request is that her friends be nicer to Britannica.
- Battlestar Galactica (2003): As the fleet hits an all-time low, Dualla, who'd been struggling to keep it together for a while now, seems to be actually getting better. She smiles more, is pleasant and even upbeat around her comrades, and even rekindles her relationship with Apollo, stating she just wants to forget about all the horrible things that have happened and have one, perfect day. After their date, she shoots herself in the head. A sudden change from depression to contentment and wanting "one perfect day" can be a fairly clear sign that the person in question intends it to be their last day.
- The Community episode "Advanced Dungeons and Dragons" has Jeff notice that classmate Neil (a frequent bullying victim) is showing signs of suicidal thoughts. He brings it up with the rest of the study group and they organize a game of Dungeons & Dragons (of which he's an avid player) to cheer him up.
- In Crazy Ex-Girlfriend season 3, Rebecca becomes extremely depressed after reacting badly to Josh leaving her at the altar and spends a few weeks lazing around at her mother's house, doing very little except constantly looking at something on her laptop. Eventually, her mom becomes curious and peeks, finding her on a page titled 'least painful ways to die'. Though she is usually very thoughtless when it comes to Rebecca's feelings, this shocks her into genuine concern for her.
- In the series finale for Father Ted "Going To America", after Ted's immigration to America is called off, Dougal celebrates that they'll be staying together in Craggy Island forever and ever, with Ted responding with a mortified Thousand-Yard Stare. In the original edit, this would have culminated in a Brick Joke with Ted joining the suicidal priest earlier in the episode on a window ledge. However, the writers' dislike for the Black Comedy ending (possibly combined with Ted's actor Dermot Morgan passing away after filming the episode) led to it being revised into a more upbeat montage sequence with Ted and Dougal heard jovially saying goodnight to each other as a closeout.
- House: Kutner is normally very, very overeager with the Magical Defibrillator, so the first time he finally uses one without any mishaps comes as a shock. He shoots himself the very next episode, and nobody ever finds out why.
- A Christmas Episode of Life in Pieces had Joan counselling a neighbor whose wife had died. She tries to tell him the warning signs of suicide... while failing to notice those same signs apply to the Short family's robot vacuum (a Roomba copy). Eventually, she admits she feels she's missed a sign... just before the vacuum throws itself down the stairs and smashes itself to pieces.
- The fourth season premiere of Orphan Black is a Whole Episode Flashback to the events that led up to Beth's suicide. Played With when it's revealed that Beth had no genuine desire to kill herself; she was blackmailed into it by Evie Cho. A lot of her outwardly strange behavior was due to her involvement in the clone conspiracy. After her death everyone misinterpreted her words and actions, assuming they were signs of suicidality when they actually weren't.
- Remington Steele: One of the biggest clues that the case in "In the Steele of the Night" is Suicide, Not Murder is that the victim has lots of dog food but no dog. Laura realizes he must have recently given away the dog he would no longer be able to care for.
- Bowling for Soup: "Goodbye Friend", which is heavily implied to be about a friend committing suicide, brings up how said friend went around telling everybody goodbye and made it clear that he and the singer were on good terms. The friend was also noticeably feeling down, making the singer desperately wish he had done more to help him back then.
- There are several warning signs that Kate is suicidal early in Life Is Strange, including her doodling pictures of nooses in her notebook and sitting in the dark in her room, Max mentioning that she's stopped playing the violin and the school's paranoid head of security noticing she's been acting strangely. She makes an attempt at the end of Episode 2; whether she survives is up to whether the player can have Max talk her down.
- The story of the Bloodbath Abnormality in Lobotomy Corporation includes a vivid description of the friend/partner of the person Driven to Suicide regretting they never noticed her increasing suicidal tendencies. It originates from Ayin's trauma of finding out Carmen slit her wrists in a bathtub.
- Doki Doki Literature Club!: After spending several in-game days being rather cheerful and ditzy, Sayori suddenly starts acting strangely and even leaves the club early one day. The player then learns she has depression and promises to help her, only for her to not show up to the Club Festival, leaving only a note that demands someone to "get out of her head" repeatedly. When the player checks on her, they find her hanging.
- Katawa Shoujo: The usually upbeat and loud Misha becomes more withdrawn throughout Shizune's arc. It's heavily implied she's suicidal and depressed, especially over her unrequited feelings for Shizune resurfacing because the protagonist is dating Shizune. This trope is even more pronounced in an earlier incarnation of her arc, which did end in her Driven to Suicide, where her depression is given more focus. Right before she kills herself, she goes shopping with her best friend and crush Shizune.
- During the Exile arc of the Dream SMP, Tommy starts talking to himself and later to Dream about how he doesn't think he has much time left, engages in openly dangerous behavior and occasional Self-Harm, and makes an effort to do things he'd always wanted to do like writing "How To Sex 3" and hanging out with Drista again. He attempts suicide after Dream destroys Logstedshire, but winds up running away instead after realizing Dream was never his friend.
- In 2018, Facebook created an algorithm that detects possible suicide notes from the social network in messages that contain words like "kill", "die" and "goodbye", making tender messages for the user, as well make a call to their friends. More information about this can be found here and here.