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.

Five Key Elements in a Psychological Thriller

By Carol Willis

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Psychological thrillers are driven by emotion and psychological tension, focusing on the minds and behaviors of their characters. They create an atmosphere of menace through plot twists, mind games, and unreliable narrators, keeping readers in suspense with a looming sense of dread. Unlike traditional mysteries, which unravel past crimes, psychological thrillers often establish the villain early, with protagonists struggling to prevent an impending threat. While they share elements with other suspense genres, psychological thrillers stand out for their deep exploration of fear and paranoia. Below are five key elements that define this gripping genre.

Atmosphere of Menace - often characterized by setting, weather, and time of day. Think secluded cabin in the woods, a spooky gothic mansion, ominous storms and in the dark of night. Usually something external that causes anxiety and uncertainty for the main character (and the reader). 

Tension and Danger - Psychological thrillers create tension by placing ordinary characters in inescapable danger, often in familiar settings like suburbs or homes. Unlike action-packed spy thrillers, these stories upend the ordinary, revealing that the greatest threats often come from those closest to us. The protagonist—often a vulnerable yet resourceful woman—must outwit a determined villain, who is frequently a spouse or family member. By rooting fear in the familiar, these thrillers immerse readers in psychological mind games, exploring themes of trust, paranoia, and hidden dangers while gradually unveiling characters’ backstories and mental struggles.

Mind Games and Psychological Manipulation - Characters experience paranoia, gaslighting, or memory manipulation. The villain often leads the protagonist in a high stakes cat and mouse game with escalating danger. The reader is made to feel as uncertain and anxious as the protagonist.

Suspense and Twists - Suspense is how an author builds tension throughout the story. It’s necessary in any genre, but it’s absolutely vital in thriller novels. Ultimately, your goal for the reader is that they never want to put the book down. Each chapter must end with a cliffhanger or significant plot twist or important question. While action does not need to be non-stop, suspense and intrigue need to be constant. There must be a sense of urgency to keep you turning the page. Emphasis is on the eerie over the sensational. Twists again are key, with chapters routinely ending in one disturbing revelation after another. Character is more important than pacing, but pacing can’t be neglected. This subgenre demands an ability to reveal dread and panic without explosions or car chases. 

Unreliable Narrator - An unreliable narrator heightens suspense by making the reader question who they can trust. Often, it’s revealed late in the story that the protagonist suffers from post-traumatic distress, mental illness, a head injury, or drug addiction, distorting their perception of reality. As noted above, lies, paranoia, and flawed memories are common in this genre, which is why many thrillers use a first-person POV. This perspective immerses the reader in the character’s experience, building sympathy while limiting their understanding to a single, potentially deceptive viewpoint—raising the crucial question: how reliable is their version of events?

Psychological thrillers focus on suspense, fear, and the uncertainty of a future crime rather than solving a past one. Unlike traditional mysteries, where the crime has already occurred, these stories often introduce the antagonist early, with the protagonist working to prevent their next move. Common elements include an atmosphere of menace, heightened tension, and psychological mind games. The genre thrives on upending the ordinary, often featuring domestic settings where danger lurks close to home. Suspense is crucial, with chapters ending in cliffhangers or shocking revelations to keep the reader engaged. An unreliable narrator, paranoia, and flawed memories add layers of intrigue, making the reader question what is real. Character development is central, with pacing maintaining a steady build-up of dread rather than relying on constant action.

In the next essay, we’ll take a deeper dive into these five key elements, exploring how they shape psychological thrillers with examples from some of the genre’s most gripping stories. Stay tuned for a closer look at what makes these thrillers so hauntingly unforgettable.

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Carol Willis (she/her) received her MFA in Writing (fiction) from Vermont College of Fine Arts. After receiving her medical doctorate from Texas A&M and an MBA in healthcare from George Washington University, she practiced child health and pathology before moving to Central Virginia. She is the author of a psychological thriller set in Chicago, a dark domestic drama exploring marriage, career, and identity. Her short stories have been published in multiple online journals and anthologies including Valparaiso Fiction Review, Inlandia: A Literary Journey, Living Crue Magazine, Crime in Old Dominion and others.