The Unreliable Narrator: How to Heighten Suspense and Keep Readers Guessing in Psychological Thrillers

By Carol Willis

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One of the most powerful tools in a psychological thriller is the unreliable narrator—a character whose perception, memory, or understanding of reality is compromised. This technique pulls readers deep into the mind of the protagonist while simultaneously keeping them at a distance, sowing doubt and suspicion. When done well, it heightens tension and fuels page-turning suspense.

In psychological thrillers, the unreliable narrator isn't just a stylistic choice—it's a structural engine. First-person narration lets readers experience the character’s inner turmoil, but what happens when that narrator cannot be trusted? Whether the cause is head trauma, substance abuse, mental illness, or sheer denial, the effect is the same: uncertainty. 

And uncertainty is the lifeblood of suspense.

What Makes a Narrator Unreliable?

Unreliable narrators are those whose version of the story is distorted by deception, delusion, or impairment. Some lie deliberately; others mislead unintentionally due to mental illness or altered states of consciousness. In psychological thrillers, the latter are especially compelling. These narrators believe what they say and yet the reader comes to understand that what they believe may not be true.

Let’s take a closer look at how several authors, Annie Ward in Beautiful Bad (2018), Tana French in The Witch Elm (2018), and Imran Mahmood in I Know What I Saw (20210) use head trauma, addiction, and psychological instability to create deeply unreliable perspectives that drive suspense and emotional tension.

Head Trauma as a Narrative Device

Set in the American Midwest, Annie Ward’s Beautiful Bad is a tightly constructed domestic psychological thriller centered on Maddie, a devoted wife and mother, her war-scarred husband, and their young son. As is typical of the genre, nothing is as it seems: buried secrets and simmering tension culminate in a shocking murder. During a camping trip, Maddie suffers a traumatic brain injury that leaves her memory fragmented. Much of the novel hinges on her attempts to piece together what really happened. Ward structures the story through short, staccato chapters and a nonlinear timeline that mirror Maddie’s cognitive disorientation. She also weaves in her husband’s PTSD and alcoholism, which amplify the emotional instability and deepen the atmosphere of dread. Readers are drawn into a fog of partial memories and unreliable perceptions, forced to navigate Maddie’s fractured psyche in search of the truth.

Tana French’s standalone psychological suspense, The Witch Elm offers a more introspective, character-driven psychological thriller, where trauma fractures not only memory but identity. Toby, a privileged and affable young man, survives a brutal home invasion that leaves him with a severe head injury and a lingering sense of cognitive instability. As he retreats to his family’s ancestral home to recover, a skull is discovered in the garden, triggering both a police investigation and a deeper unraveling within Toby himself. French masterfully entwines the external mystery with the internal one: who was Toby before the attack, and can he trust the person he is now? The narrative blurs the line between guilt and innocence, perception and denial. Toby’s unreliable memory becomes the novel’s engine of suspense, compelling readers to question not only what happened, but whether Toby himself might be capable of violence he can no longer remember.

Imran Mahmood’s I Know What I Saw (2021) offers another powerful example of how head trauma can fracture both memory and identity. The narrator, Xander Shute, is a once-successful barrister now living on the streets of London. When he accidentally witnesses a murder in what he believes is a break-in gone wrong, he reports it only to be told by police that no such crime occurred, and the apartment is occupied by a completely different couple. What follows is a tense unraveling of Xander’s mind. His past trauma, mental health struggles, and head injuries blur the line between what he remembers and what may have never happened at all. Mahmood uses fragmented memories, dreamlike logic, and time slippage to keep the reader guessing: Is Xander witnessing a conspiracy, or is he caught in the spiraling aftermath of untreated trauma? His voice is sharp, intelligent, and self-aware. Yet the more he insists on what he saw, the more readers question whether they should believe him.

Other Forms of Unreliability

Substance abuse is another common and highly effective device in thrillers. Alcoholism and drug addiction introduce uncertainty, distortion, and mistrust—the perfect ingredients for narrative suspense. These altered states skew perception, bend time, and create memory gaps that leave both the character and the reader struggling to connect the dots. In Paula Hawkins’s The Girl on the Train (2015), for example, blackouts erase entire chunks of the protagonist’s experience. The narrator becomes both detective and suspect, trying to solve a mystery she might have unwittingly caused.

Mental illness—especially dissociation, anxiety, and PTSD—can also destabilize a narrator’s grasp on reality. A character may be telling the truth as they see it, but that version of events is filtered through trauma, fear, or delusion. These internal fractures not only add emotional complexity but also keep readers questioning what’s real, and what’s imagined.

Why It Works

Unreliable narrators heighten suspense by withholding clarity. In a genre driven by twists and revelations, these characters provide fertile ground for ambiguity. The reader doesn’t simply ask, "What will happen?" but, more compellingly, "What is really going on?"

Unlike thrillers that rely solely on external threats, psychological thrillers with unreliable narrators turn the narrative inward. They make the protagonist’s mind the true battleground. The suspense comes not only from what the character might do, but from whether they even know what they are capable of.

For Writers: Using Unreliability to Build Suspense

Start with character: What might your protagonist be unwilling or unable to see clearly? Consider layering trauma, denial, or dependence on substances to introduce narrative distortion.

Use memory loss or selective recall to reveal truths in increments. Structure scenes around flashbacks, contradictions, or moments where the narrator second-guesses themselves. Let your setting mirror the character’s instability—fog, rain, locked rooms, or chaotic domestic spaces can reinforce psychological disarray.

And most importantly, root the unreliability in emotional truth. Readers don’t need to trust your narrator to follow them—they just need to believe in their struggle. Suspense thrives in this space between belief and doubt.

Character as a Haunted House

By Aimee Hardy

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Establishing engaging and relatable characters is one of the most important parts of storytelling. Characters should have compelling backstories, relatable flaws, and fulfilling character arcs, but one of the best tools that I’ve learned about creating characters is to think of them like a haunted house. 

Each house has a facade that everyone sees. This is usually the most complimentary view of the house. Passersby can admire the paint, the sweeping porch, and the manicured lawn. Everything is usually neat and tidy, and all its secrets are safely locked away inside. Even haunted houses look best from the outside. 

Similarly, everyone sees certain aspects of a character. This is the image they present to society. It’s the suit jacket worn for status, the combat boots worn for protection, the high heels worn for seduction. It’s the gruff voice to establish dominance or the motherly coo to show nurturing, the helping hand they give when on the train or the kind words said at the gas station. These are the outward images that we must establish from the very beginning because they show how the character would like to be seen from the outside. 

Friends are allowed access inside the house, however. Acquaintances are invited in and can see the common rooms. Those rooms are still cultivated, yet they are a little more intimate. As acquaintances become friends or loved ones, they are invited further inside the house. They see the dishes that have been piled in the sink, the laundry that is overflowing, or the tub that is in need of a good scrub. In a haunted house, we can see the evidence of ghosts. We can hear strange footsteps, feel cold spots, and see apparitions, but we can’t quite determine what is haunting the house. 

Just as with houses, our characters will reveal more intimate details about themselves (and their own ghosts) as they make bonds with other characters and as we (the reader) get to know them in the story. We can see that they are kind by the way they treat their loved ones but that it hurts when no one says thank you. We can see that they are jealous of an adversary, but we can also see that it’s because they were never given the same opportunities to be great. We can see that they are smart but that they are terrified of losing their top spot. They become nuanced–both kind and resentful, jealous and righteous, smart and insecure. 

Then, there are rooms in this haunted house that are so scary that the main character would not dare to enter. These rooms contain the worst secrets that will not leave us alone, and with characters, these rooms contain their deepest fears. The kind and resentful mother might fear that she isn’t worthy of being loved. The jealous and righteous bully might be afraid of being weak or controlled by others. The smart but insecure scientist might fear they are useless. The main character is haunted by these fears and can’t move on until they confront their ghosts. 

So, when I write stories, I always ask what is haunting my main character. If they are worried that they have no identity, maybe they fill their “rooms” with collections. They might appear to know a lot of things in their search for their identity and might even adopt different identities as they interact with different characters. On the outside, they might overcompensate by wearing elaborate costumes or may even be so insecure that they only wear black. However you design your character, keep in mind that their house is haunted, and that in the end, their ghosts will have to come out. 

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Aimee Hardy is a writer and editor in Birmingham, AL. She is the author of Pocket Full of Teeth (September 2024 Running Wild Press). She has been published in Stonecoast Review, Running Wild Press’ Short Story Anthology, Havik2020, Bluntly Lit Mag, Adelaide Literary Magazine, and Lost Pilots Lit and was nominated for the Pushcart Prize in 2020. She has a B.A. and M.A. in English from National University. When she’s not writing or editing, she enjoys going on hikes with her husband and two kids or curling up with a good book and a hot cup of tea. For more of Aimee’s work, please visit www.aimeehardy.com.