9 Tips for Writing an Insane Character

tiana warnerGuest Post
by Tiana Warner

Nothing beats a good insane character. They’re unpredictable, obsessive, totally spellbinding … and hard to write. Their arcs and motivations can differ completely from ordinary characters. Saying you’re going to write an insane character, however, is like going to a steakhouse and ordering a beef and a wine. You need to get specific. There are about a million types of crazy.

I spent two years studying some of the best crazy characters in order to understand what works best. I even took a university class on abnormal psychology. (Yeah. I went there.) Through it all, I came up with nine ways to intensify the character. For those of you looking to lose your fictional marbles, let me share what I’ve learned.

1. He is a man-vs-self conflict

This character is his own antagonist. Take everything you know about the relationship between protagonist and antagonist, and apply those rules to the sane and insane parts of the character.

For example, we know the antagonist should share a lot of qualities with the protagonist, except for a key moral difference. What flaw is splintering your character’s sanity? Is it alcohol abuse, as in The Shining? Jack’s descent into madness literally changes his character from protagonist to antagonist.

2. He deeply affects other characters

Many crazies are master manipulators: Annie Wilkes (Misery), Esther (The Bell Jar), Lisa (Girl, Interrupted), and of course Fight Club. Yes, others follow Tyler Durden because he’s charismatic — but also because they’re terrified of the guy. Putting your character in a position of power adds layers of tension, because that crazy antagonist suddenly has a wider reach.

Raise the stakes by ensuring the character’s loved ones are affected. Look at the intense moments in A Beautiful Mind: when John Nash leaves his baby in the tub because he’s preoccupied with his hallucinations, or when his hallucinations tell him to kill his wife. The punch comes from our wondering whether he’s going to hurt people he loves because of a lapse in sanity.

3. His arc is driven by obsession

In Silver Linings Playbook, Pat is driven by obsession with his ex-wife. In Misery, Annie’s obsession with Paul Sheldon gets downright horrifying. For these characters, obsession is a side effect of having a screw loose, but it can also go the other way.

In Black Swan, Nina’s obsession with becoming the perfect ballerina drives her to insanity. One plot peak marks a turning point from Passive Nina to I-Get-What-I-Want Nina. A second peak marks a turning point from I-Get-What-I-Want Nina to You’ll-Die-If-You-Get-In-My-Way Nina. They are pivotal in showing how desperate she is to achieve her goal. Give your insane character these moments!

4. He probably knows something’s not quite right

Writing insane characters offers a fantastic chance to use dramatic irony. Does your reader know more about the character’s sanity than the character herself? Or does your character have an inkling that something’s off? You need to decide what your character thinks of herself.

In Still Alice, Alice knows she’s losing her mind and knows when she’s being weird — at least until the Alzheimer’s completely overtakes her. Maybe your character knows something’s not right (where are those voices coming from?) but thinks she can control it.

5. He shows symptoms of a real mental disorder

Ok, the vast majority of real mental disorders are less psychotic than what we see in books and movies. However, insane characters should still have disorders rooted in fact. Study the real thing — the science will inspire you. Look up blunted affect, anhedonia, asociality, thought disorder, catatonia, and other interesting symptoms you stumble across in the Diagnostic and Statistical Manual of Mental Disorders.

In Fatal Attraction, Alex Forrest probably has borderline personality disorder — a condition that makes for particularly fun cinema. (By the way, anyone else still find molasses-covered Glenn Close more terrifying than bunny-boiling Glenn Close? No? Just me? Ok.)

Most insane characters seem to have an escalated version of psychosis. This disorder is worth researching, from the early signs (social withdrawal, sleep disturbance, anxiety…) to full-blown delusions, hallucinations, and speech problems.

6. He has behavioural quirks

Quirks can range from simple to totally whacked-out behavioural patterns. In A Beautiful Mind, John touches his forehead when he’s nervous. Simple, but the way he does it is strange, indicating something’s off.

Watch the way Helena Bonham Carter plays Ophelia in Hamlet. That chick is one fry short of a Happy Meal. Clenching fists, overflexed fingers, childlike playfulness, outbursts, rapidly changing moods, and the general greasy appearance are spectacular.

For a grand finale, watch The Dark Knight and skip to all parts involving The Joker. Holy psychopath, Batman.

7. He ignores primal urges

Normal characters have goals centred around a primal urge. Avoid hunger. Get the girl. Take my hand away from that burning sensation.

Insane characters are not like this.

In A Beautiful Mind, John’s obsession takes priority over everything else, including sex and food. In The Bell Jar, Esther goes a whole week without sleeping. In Fight Club and Black Swan, the characters self-mutilate.

8. He was set off by something

What triggered your character’s descent into madness? You may choose to show the trigger in your plot, or mask it as backstory.

Mental disorders have a variety of causes. Why does your character have this disorder? Was her mom bipolar? Is it drug-induced psychosis? Did she have a traumatic experience as a child? Again, use science to inspire you.

In Black Swan, we clearly see that Nina’s problem comes from her mother. Early on, she shows symptoms of an anxiety disorder (she scratches herself in her sleep, throws up, etc.). Eventually, tests and trials make her problem escalate into full-blown psychosis.

9. The Snap moment

This is the moment we’ve all been waiting for, when your character goes totally bananas. The “Here’s Johnny!”, the “It’s my turn!”, the “You wanna know how I got these scars?” moment. Have fun with this! A crazy character’s Snap moment is probably the most fun thing to write. Like, ever. In the history of time.

Note that an insane character doesn’t have to be doomed. Silver Linings Playbook and A Beautiful Mind end with triumphs over the madness. In these films, the Snap happens during the “all is lost” moment when we think the character has lost to his insanity — but the character ultimately triumphs during the climax.


Figure out what arc you want your character to take, what obsession drives his madness, and what behavioural quirks he’ll have. Does his story end when he overcomes his obsession, as in Silver Linings Playbook? Or does her story end with her screaming “It’s my turn!” and doing some serious damage with a glass shard, as in Black Swan?

If you’re preparing to write an insane character, I do recommend you study the books and movies I reference. (Maybe bring a friend, because the movies are slightly terrifying.)

Who’s your favourite insane character? What books or movies can you recommend? (Really, please recommend. I will read/watch them!)

Tiana Warner was born and raised in British Columbia, Canada. She enjoys riding her horse, Bailey, and collecting tea cups. Her new YA fantasy, Ice Massacre, is now available, and proves she thoroughly lost her fictional marbles. Learn more about Tiana on her website or her Author Central page.

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25 thoughts on “9 Tips for Writing an Insane Character”

  1. These are wonderful tips, Tiana, and kudos to you for your in-depth research. I recently read a book in which the author had apparently looked up a list of bipolar symptoms online and assigned them randomly to her crazy character, without realizing that some symptoms are associated with the manic phase and some with the depressive phase. I’m no psychiatrist, but even I knew *that* was wrong. 😀

    1. Thanks, Lynne. That sort of mistake is definitely something writers need to avoid! Insanity might seem synonymous with unpredictable, but it does have patterns and symptoms that we need to be mindful of. (pardon the pun?)

  2. It’s important to note that most depictions of “insanity” are literary constructs and have little or nothing to do with real mental illness. As long as we are clear that the “insane” antagonists of most mystery and suspence stories are as much a device of fantasy as Tolkien’s elves, dwarves and hobbits, then we are ok. The further question then becomes, why are we so fascinated with these imaginary creatures?

    1. Totally agree, Robert! That’s one thing I found for sure: “movie insane” is very different from “real life insane”. I’m not sure why the cinematic kind is so fascinating, but they sure are fun to watch/read. I imagine it has something to do with the suspense caused by their behaviour.

      1. A lot of suspence plotting involving so-called “insane” characters devolves to the level of a college sophomore late-nite bull session. “What is the guy is just SO crazy that he does something that would never happen in real life, like monologing to the hero while threatening his family with nuclear annihilation?”

  3. Great post, Tiana. Robert makes an interesting point. People who are truly mentally ill tend to be out of control and without a lot of malicious intent. In most fiction we’re talking about sociopaths, who are very much in control and like being wicked. I think people call them insane, because we used to put such people in “homes for the criminally insane” (or at least, that’s what happened to Gotham’s baddies).

    But, I diverged from the original post for a second there. Love the archetypes. Number 7 is probably my favorite. I like those who ignore their primal urges to exact their wicked plans.

    1. Thanks RJ. You make a good point: when the crazy character is the antagonist, “like being wicked” tends to be a key trait. Gotham’s baddies are probably a very good point of reference!

  4. I watch “The Forensic Files” – a true crime documentary. (30 minute episodes) They don’t always explain the motivation of the perpetrator since their focus is on forensics, but occasionally, when the perp confesses, they will. One killer admitted to randomly murdering a woman (the hardest type of murder to solve) because he was about to be convicted as a child molester and thought it would be better to be known “inside” as a cold-blooded killer. I highly recommend that show.

  5. Wonderful post Tiana. You made it interesting, useful and at the same time fun. Nothing wrong with a little quirky behavior? Right? 😉

    Thank you.

  6. I find it interesting that you draw most, if not all of your examples from film, rather than literature. That aside, my favorite “insane” characters are those that have a quality of ambiguity to them, rather than the outright psychopaths; those who reject or simply refuse to accept commonly held concepts of morality, beauty and other subjective values. A prime example of this would be Kurtz in Conrad’s “Heart of Darkness”. Marlow and most of the other characters in the novel are also tinged with madness and obsession. Regardless of what you think of the colonial and racial aspects of “Heart of Darkness”, which are products of its time, it is the ambiguity of its characters that make it great. It forces us to face Conrad’s assertion that sanity itself is a subjective measure.

    1. Thanks for the recommendation, John. I haven’t read Heart of Darkness yet so I’ll add that to my list.

      There are a few examples from books (or books-turned-movies), but I admit I studied more movies than books on the subject! I like watching the character’s behaviour as interpreted by actors. Provided the acting is good, I think stories that are both books and movies (Fight Club, Misery, The Shining…) are the best to study, since we can see how the author wrote it and then watch how it plays out on a screen.

  7. In Ripple I have an insane dolphin who kills and then commits suicide by stranding. It is inherited insanity. I needed to give Cosmo experience of of true insanity, so he could later be the one who saw through Ripple’s supposed insanity quicker than most others.
    The pain he feels while dying on the sand cures his insanity at the end. He’s happy with the deal as he finds the physical pain preferable to the madness.
    I do wonder of the very few modern dolphins who have been observed behaving aggressively towards others of their own kind have become insane through the poisons they ingest in the fish they eat which are now loaded with human pollutants like mercury. I couldn’t allow this to be the cause of the insanity in Ripple since the story is pre-human – so no mercury.

    1. That’s such a unique premise! I’ve read that dolphins are quite possibly as intelligent as people, so this idea intrigues me. I like how you juxtapose his physical and mental pain at the end. Nice way to resolve it.

  8. Thought provoking post, Tiana. Personally, through a long and extremely varied life style, coming into contact with an inordinate number of people from all walks of life, I have come to the conclusion that sanity, or the lack of it, is merely a matter of perspective. I have known people who would be clinically designated as psychopaths or sociopaths; from those I have known personally, probably as many as twenty, to my knowledge only one actually became a killer; I mean an actual hitman, an assassin.

    1. “sanity, or the lack of it, is merely a matter of perspective.” Good insight. That’s very true. In real life, diagnosis is an alarmingly subjective process… It’s certainly not as clear (or extreme!) as what we see in movies and books.

  9. Very Nice Read! My favorite foray into insanity is a classic, Raskolnikov in Dostoyevsky’s “Crime and Punishment”. Thank you again.

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