Pathological lying is not currently classified as a standalone mental illness. It does not appear as its own diagnosis in the DSM-5-TR, the manual clinicians use to diagnose psychiatric conditions. However, that doesn’t mean it’s simply a character flaw or a bad habit. Pathological lying sits in a gray area: it frequently accompanies recognized mental health conditions, it has measurable differences in brain structure, and many clinicians believe it causes enough distress and dysfunction to warrant its own classification.
Why It’s Not an Official Diagnosis
The only place pathological lying gets a direct mention in the diagnostic manual is in connection with factitious disorder, a condition where someone fabricates illness for attention or sympathy. Beyond that reference, it has no formal criteria, no diagnostic code, and no official threshold that separates it from ordinary dishonesty. This gap has frustrated researchers for over a century. The behavior was first described in medical literature in 1891 by German physician Anton Delbrueck, who noticed that some patients told lies so extreme and disproportionate to reality that he couldn’t fit them into any existing diagnosis. More than 130 years later, the classification problem remains unresolved.
The core issue is that researchers still lack enough clinical evidence to determine whether pathological lying is a distinct condition or always a symptom of something else. Questions remain about whether it presents consistently enough across people and cultures to define clear diagnostic boundaries. Without a formal diagnosis, there are no standardized treatments and limited research funding to study it, which creates a cycle where the condition stays poorly understood precisely because it isn’t officially recognized.
Conditions It Commonly Appears With
While pathological lying may not stand alone in the diagnostic manual, it frequently shows up alongside recognized psychiatric conditions. The most common associations include antisocial personality disorder, narcissistic personality disorder, and borderline personality disorder. In borderline personality disorder, deception often serves as a way to prevent perceived rejection or abandonment. In antisocial personality disorder, lying tends to be more calculated and self-serving.
Pathological lying also appears in people with bipolar disorder, ADHD, impulse control problems, and substance use disorders. Factitious disorder (sometimes called Munchausen syndrome) involves a very specific form of pathological lying focused on faking or inducing illness. So if someone is lying persistently and in ways that seem out of proportion to any obvious benefit, there’s a reasonable chance an underlying condition is driving the behavior. But researchers have also documented cases where chronic, extreme lying occurs without any other diagnosable psychiatric disorder, which is part of why the debate over its status continues.
Brain Differences in Pathological Liars
One of the most compelling arguments for treating pathological lying as more than just a behavioral choice comes from brain imaging research. A study published in The British Journal of Psychiatry found that people identified as pathological liars had 22 to 26% more white matter in the prefrontal cortex compared to both normal controls and people with antisocial personality disorder. White matter consists of the neural wiring that connects different brain regions, and the prefrontal cortex handles planning, decision-making, and complex thought.
The researchers also found a 36 to 42% reduction in the ratio of grey matter to white matter in the same brain region. Their hypothesis: this extra wiring may give pathological liars greater cognitive capacity for constructing and maintaining elaborate false narratives. In other words, the brain structure that supports lying may develop differently in these individuals, suggesting a biological component rather than purely a moral failing.
How Childhood Experiences Play a Role
Not all pathological lying traces back to trauma, but early life experiences can set the stage. Children who grow up in environments where honesty leads to punishment, criticism, or rejection sometimes learn that lying is the safest option. Over time, this survival strategy can harden into an automatic pattern. A child who discovers that deception prevents conflict or reduces stress will repeat the behavior until it becomes deeply ingrained.
Trauma can also disrupt the development of trust and secure attachment, making open, honest communication feel genuinely threatening well into adulthood. The severity, timing, and type of adverse experiences all influence whether this pattern develops, along with personal resilience and the quality of social support. Plenty of people who experienced difficult childhoods never develop compulsive lying, and pathological lying doesn’t automatically indicate a trauma history. But for a significant subset of pathological liars, the roots reach back to early coping mechanisms that once made sense but became maladaptive.
What Treatment Looks Like
The lack of a formal diagnosis creates a real practical problem: without official recognition, there are no empirically validated treatments specifically designed for pathological lying. That said, clinicians aren’t working completely in the dark. According to researchers who have surveyed therapists and studied the condition, cognitive behavioral therapy is considered the most promising approach. The core idea is helping the person become aware of when and why they lie, then systematically reinforcing honest behavior instead.
Behavioral techniques like habit reversal training encourage people to notice the urge to lie in the moment and choose a different response. Group therapy also shows promise for a practical reason: other group members can call out dishonesty in real time, which removes the burden from the therapist and creates social accountability that’s hard to replicate in one-on-one sessions.
The honest answer to “can pathological liars get better?” is that clinicians don’t yet have enough data to say definitively. The absence of a formal diagnosis means there’s been little systematic research into what works, how long treatment takes, or what recovery rates look like. Many therapists remain optimistic that change is possible, particularly when the lying is connected to a treatable underlying condition. But the field is still in early stages of understanding what effective intervention looks like for people whose primary problem is the lying itself.
Where the Line Falls Between Habit and Disorder
Everyone lies sometimes. Research consistently shows that ordinary people tell one or two lies per day on average, mostly small social lubricants. Pathological lying is different in scale, complexity, and persistence. It involves falsification that is disproportionate to any obvious purpose, often elaborate and detailed, and continues over years or even a lifetime. The lies frequently don’t serve the person’s self-interest in any clear way, which distinguishes them from the calculated deception seen in con artists or fraud.
Whether this pattern qualifies as a mental illness depends partly on how you define the term. It causes real harm to relationships, careers, and the liar’s own wellbeing. It appears to have biological underpinnings. It resists simple willpower to stop. By most functional definitions of mental illness, pathological lying checks many of the boxes. The psychiatric establishment simply hasn’t caught up to that reality with a formal classification, leaving people who struggle with compulsive dishonesty in a diagnostic no-man’s-land where the behavior is clearly abnormal but doesn’t yet have a clinical home of its own.