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Pathological Lying: Symptom or Disease?

By Charles C Dike, MD, MPH, MRCPsych

Pathological lying (PL) is a controversial topic. There is, as yet, no consensus in the psychiatric community on its definition, although there is general agreement on its core elements. PL is characterized by a long history (maybe lifelong) of frequent and repeated lying for which no apparent psychological motive or external benefit can be discerned. While ordinary lies are goal-directed and are told to obtain external benefit or to avoid punishment, pathological lies often appear purposeless. In some cases, they might be self-incriminating or damaging, which makes the behavior even more incomprehensible. Despite its relative obscurity, PL has been recognized and written about in the psychiatric literature for more than a century. The German physician, Anton Delbruck,1 is credited with being the first to describe the concept of PL. He observed that some of his patients told lies that were so abnormal and out of proportion that they deserved a special category. He sub-sequently described the lies as “pseu- dologia phantastica.”

Case Vignette

Mr A was desperate. He was about to lose yet another job, not because he was at risk for being fired, but because his lying behavior had finally boxed him into a corner. He had lied repeatedly to his colleagues, telling them that he had an incurable disease and was receiving palliative treatment. Initially, his coworkers treated him with sensitivity and concern, but as the weeks wore on, the scrutiny of his colleagues became increasingly pointed. He had to tell more and more outrageous lies to cover his tracks and justify having a terminal illness. Finally, when the heat became too unbearable, he suddenly stopped going to work. On the face of it, it would seem Mr A told these lies to gain the sympathy of his colleagues, but the consequences of his lying, in terms of emotional distress and potential loss of job, far outweighed any perceived gain. Mr A had lost several other jobs in the past because of his lying, and he was becoming frustrated. Family members reported that he often told blatant lies, and even when confronted, and proved wrong, he still swore they were true. Mr A finally sought psychiatric help after concluding that he could not stop himself from lying.

This scenario, or similar stories, is not uncommon in clinical practice. Letters I have received from mental health professionals, attorneys, and individuals around the world describe similar characteristics in people they know—excessive lying, easily verifiable to be untrue, mostly unhelpful to the liar in any apparent way, and even possibly harmful to the liar, yet told repeatedly over time. Even prominent and successful individuals are not immune to this behavior—for example, the well-known California case of Judge Patrick Couwenberg, who was removed from office not only for lying in his official capacity but also for lying under oath to a commission investigating his behavior.2 A psychiatric expert witness diagnosed pseudologia phantastica and suggested that the judge needed treatment. Why such a successful individual would repeatedly tell lies that could damage his credibility and put him in trouble with the law or other administrative bodies is baffling. Was his lying behavior completely within his control, or was there something different about his pattern of lies?

Lying is a common human trait defined by Merriam-Webster’s Collegiate Dictionary as making “an untrue statement with intent to deceive.” Selling3 agreed, with an observation that “everyone lies and you can’t stop them,” and concluded, “of course, that is the truth.” PL is commonly referred to as pseudologia phantastica (or pseudologia fantastica) and, less commonly, as mythomania, or morbid lying. It is not yet clear whether these different names refer to the same phenomenon, but they are often used interchangeably. Throughout this article, PL and pseudologia phantastica will be used synonymously.

Over the years, very little has been written on the epidemiology of PL. Although its prevalence in the general population is unknown, one study of 1000 repeat juvenile offenders found a prevalence of close to 1%.1 A review of 72 cases reported that the average age at onset of the lying behavior was 16 and the average age at discovery was 22.4 The same review showed the sex ratio to be equal; the intelligence quotient (IQ) to be average or slightly below average, with significantly better verbal IQ than performance IQ; and a history of CNS abnormality in 40% of the cases, characterized by epilepsy, abnormal electroencephalographic findings, head trauma, or CNS infection.

PL is noted for the chronicity and frequency of the lies, and the apparent lack of benefit derived from them. The lies are easily disprovable tales that are often fantastic in nature and may be extensive, elaborate, and complicated. There often appears to be a blurring of the boundaries between fiction and reality. The magnitude, callousness, or consequences of the lying behavior are irrelevant. Even when there appears to be an external motive for the lies in PL, the lies are so out of proportion to the perceived benefit that most people would see them as senseless. Such characteristics of PL have led some researchers to conclude that the lying behavior appears to be a gratification in itself,5 the reward is internal (usually unconscious) to the liar, unlike ordinary lies, for which the expected reward is external.

Controversy surrounding PL

The debate over the ability of pathological liars to recognize their lies as false has dogged this phenomenon for decades. Integral to the debate is the confusion emanating from questions about a pathological liar’s ability to think logically. It has been observed that pathological liars believe their lies to the extent that the belief may be delusional. As a result, PL has been referred to as a “wish psychosis.”1 Furthermore, PL has also been described as impulsive and unplanned.1 These observations have raised doubts about the pathological liar’s ability to fully control his or her lying behavior. The relative purposelessness of the lies, including the intangible benefits of false accusations or self-incrimination, and the repetitive nature of the lies, despite negative consequences to the liar’s reputation and livelihood, further encourage doubts about the liar’s ability to control his behavior. On the other hand, it has been observed that vigorously and persistently challenging pathological liars may lead pathological liars to partially acknowledge their lies, an observation that suggests the presence of logical thinking.6 Such a presentation is consistent with a view of PL as a fantasy lie, a daydream communicated as reality, told solely for the liar’s pleasure.5 Although the fantasy lies may help the pathological liar escape from stress-ful life situations, or compensate for developmental traumas, there is evidence that individuals with PL show normal “guilty responses” when lying during a lie-detection test.7 It is perhaps an attempt at guilt reduction that motivates pathological liars to believe their lies, thereby creating a strange form of double bind.

The further observation that pathological liars usually have sound judgment in other matters and the observed association of PL with other criminal behavior in approximately half of the cases supports the notion of intact reality testing. The crimes associated with PL include theft, swindling, forgery, and plagiarism.4 It is worth noting, however, that some pathological liars are successful professionals without any public record of crime.

Differential diagnosis

PL should be differentiated from other psychiatric conditions that have been associated with deception. This is complicated because lying behaviors that mimic PL have been described in certain personality disorders and in factitious disorder. The core symptoms of those personality disorders—antisocial, borderline, histrionic, and narcissistic—are often apparent. For example, the falsifications that may occur in borderline personality disorder (BPD) are not usually of the elaborate, fantastic, or complicated nature seen with PL. Patients with BPD often lack a consistent self-identity, hold contradictory views of themselves that alternate frequently, often make false threats, and are prone to false accusations of maltreatment and/or abandonment. Conversely, pathological liars do not show the intense affective dysregulation or suicidal behaviors that characterize BPD. In antisocial personality disorder, the lies are often for external gain, and there is a history of conduct disorder in childhood, unlike in PL. Furthermore, the lying behavior in PL covers a wider context than in factitious disorder, in which lying is solely for the purpose of assuming a sick role.

Other conditions that could be confused with PL include malingering, Ganser syndrome, and confabulation. The elaborate and complicated fantasies seen in PL do not occur in Ganser syndrome, where the lies are limited to approximate answers, or in confabulation (which may be part of the descriptive symptoms of Wernicke-Korsakoff syndrome), where falsifications are used to cover memory gaps. Furthermore, there is no organically derived amnesia in PL as exists in confabulation. The feature that differentiates malingering from PL is the motivation for lying; obvious external incentives alone drive the lies in malingering, unlike in PL, where the motivation to lie is less clear.

Delusions should be considered in the differential diagnosis because of controversial propositions that the lies told in PL rise to delusional proportions. Unlike PL, however, delusions are not intentional lies told to deceive, but rather, they are fixed beliefs that happen to be false. The blurring of fact and fiction that occurs in PL is not the same as the absolute conviction that occurs in persons with delusions.

Other diagnostic conundrums

In their seminal report, Healy and Healy1 argued that true PL occurs in the “absence of definite insanity, feeblemindedness, or epilepsy,” an opinion that indicates PL is not secondary to another psychiatric disorder. This opinion has not been universally accepted; counter arguments posit that PL is always secondary to a recognizable psychiatric disorder.3 The only mention of PL in DSM is as a non- essential symptom of factitious disorder.

Ironically, lying to assume a sick role is considered important enough to warrant a diagnostic label; but PL, which, like factitious disorder, has an unconscious motive, is not. It is becoming increasingly clear, however, that there are individuals with PL who have no preexisting psychiatric disorder. For example, Judge Couwenberg’s psychiatrist expert witness diagnosed pseudologia phantastica. Going back in history, Cleckley8 described the case of a successful and respected man with a doctorate in physics who had pseudologia phantastica in the absence of insanity or psychopathy. Consequently, Dike and colleagues9 have suggested that PL should be categorized as primary PL or secondary PL, depending on the absence or presence, respectively, of a preexisting psychiatric disorder that might be responsible for the lying behavior.

If PL cannot be considered a clinical entity in its own right, could it be seen as a subset of the impulse control disorder spectrum, given the impulsive nature of the lies? Alternatively, does the observation that pathological liars feel compelled to lie repeatedly, or have obsessional falsifications (according to Fenichel10), warrant a consideration of PL as an obsessive-compulsive disorder? A more controversial consideration would be whether there are subtypes of pathological lying that may fit into a special category of delusional disorders— especially in those whose reality testing is suspect. To suggest, however, that PL is a psychotic disorder would seem preposterous to most psychiatrists because individuals exhibiting PL often function well in many spheres of daily living. Although the cause of PL is unknown, there are increasing associations with CNS dysfunction. As noted earlier, 40% of 72 individuals with pseudologia phantastica had a history of CNS abnormalities.4 In another study, single photon emission CT showed right hemithalamic dysfunction in a patient with pseudologia phantastica.11

The most recent study involved the use of structural MRI in 12 individuals identified as “liars.”12 The liars group comprised 4 subgroups: malingering group, PL group (PL was defined using the Hare Psychopathy Checklist–Revised), individuals with conning/manipulative behavior, and individuals who met the deceitfulness criteria for DSM IV. The study found a 22% to 26% increase in the prefrontal white matter and a 36% to 42% reduction in prefrontal gray-to-white ratios in the liars group compared with antisocial controls and normal controls. The main flaw of this study was that although half of the liars group had a diagnosis of malingering and only a small number had PL, the liars group was frequently interchanged with the pathological liars as if they were the same. In addition, PL was defined using the Hare Psychopathy Checklist, an indication that the few pathological liars included in the study were those with criminal behavior and psychopathy.

To ascribe observations from this study to PL is therefore problematic and misleading; PL and malingering are different entities, and most pathological liars are not psychopaths. There is no specific psychological test for PL. However, psychological tests would help in elucidating the presence of personality disorders, other major psychiatric illnesses, or malingering. PL has been at the fringes of psychiatric practice for more than a century. It is not surprising, therefore, that it remains ill understood and poorly researched. The increasing interest in the phenomenon in recent years, and the availability of high-tech radiological investigations may reverse this trend and help answer the many questions that have dogged this phenomenon. Despite the fact that psychiatrists are slowly converging on a uniform definition of PL, it remains unclear whether it is a mental disorder or merely behavioral excess. Associated questions involve the treatability of the phenomenon, available treatment modalities, and outcome of treatment. A psychiatrist representing Judge Couwenberg’s defense team opined that pseudologia phantastica was treatable with therapy but did not state the basis for his assertion.


The options available for treating PL have been poorly researched. The treatment modality mainly discussed in the literature is psychotherapy. However, there are no systematic studies on the effectiveness of psychotherapy in treating PL and no discussion of pharmacotherapy or any other types of interventions. It is possible that there may be a subset of pathological liars for whom pharmacotherapeutic options may help in reducing impulsivity or the compulsions associated with the urge to lie. In addition, further investigation of CNS abnormalities may lead to other therapeutic interventions. To fully embark on an exploration of treatment options for PL, however, it should first be recognized as a diagnostic entity. PL currently exists as a common but unessential symptom of factitious disorder. As in other medical or psychiatric conditions, emphasis is usually on the treatment of the condition as a whole and not necessarily the treatment of its individual symptoms.

Therefore, PL should be recognized as a diagnostic entity to encourage research into its treatment. The possible consequences of PL for the liar are severe. All relationships of the liar are at risk for destruction resulting from lack of trust and credibility. The shame of socially or formally interacting with others in the company of a spouse who lies repeatedly could overwhelm the relationship. In the workplace, as their lying behavior becomes increasingly clear to their colleagues, pathological liars stand the risk of bearing the brunt of rude jokes, being alienated, or being fired. In clinical situations, the therapist has the arduous task of overcoming not only the negative countertransference of treating a habitual liar but also the frustrations of not knowing which of the patient’s statements are true.

Although most individuals affected with PL may not have cause to seek treatment and may indeed continue to lead highly successful and productive lives, it is not uncommon for their lies to cause them hardship through clashes with the law or other authorities, with resulting adverse consequences. For example, a purposeless false accusation, a recognized presentation of PL, is a criminal behavior for which the pathological liar may be prosecuted. This type of false accusation should be differentiated from false accusations for revenge purposes, or those that may occur in mass hysteria (for example, the Salem witchcraft phenomenon), in which a false idea generates intense anxiety that quickly spreads and may lead to baseless accusations.

Forensic issues

It is perhaps in the forensic psychiatric arena that the need to clearly define PL is most urgent. The immediate question in these settings would revolve around the issue of competency of the pathological liar to stand trial. The criteria for being competent to stand trial include an ability to work collaboratively with one’s attorney in order to confront one’s accusers. A defendant who lies frequently and repeatedly to his attorney would ultimately confuse the attorney, making it difficult to formulate a sound strategy of defense.

Another problem is the risk of the pathological liar being accused of perjury when he gives false testimony under oath. In the case of Judge Couwenberg, the State of California Commission of Judicial Performance noted that he did not have a mental condition that excused or mitigated his behavior. The commission concluded that the mere presence of a symptom without any mental disorder is of little legal consequence.

It is easier to argue that PL is not a delusion than it is to say that pathological liars always have control over their lies.

Koppen13 observed that the lie ultimately wins power over the pathological liar, so that mastery of his own lies is lost. In addition, PL has a compulsive or impulsive quality. Would it be feasible to say that in some cases the lying behavior was uncontrollable? Such a conclusion, when combined with recent evidence of possible CNS abnormalities in PL, would raise doubts about the degree of responsibility of pathological liars when their lies lead to criminal behavior.


In conclusion, PL is a special form of lying, narrow in its definition and complicated in its presentation. Its apparent rarity may be the consequence of lack of awareness of the phenomenon by clinicians. Unfortunately, it periodically causes significant hardship to the pathological liar. Psychiatrists confronted with pathological liars should complete a thorough clinical evaluation and obtain a longitudinal history of their lies, especially through collateral information from relatives, friends, and employers. In addition to psychotherapeutic treatment, psychiatrists should consider research into the usefulness of pharmacotherapy for impulsivity or compulsive behaviors in these patients.

Dr Dike is division medical director at Whiting Forensic Services at the Connecticut Valley Hospital in Middletown, and assistant clinical professor in the division of law and psychiatry of the department of psychiatry at Yale University School of Medicine in New Haven, Conn. He reports that he has no conflicts of interest concerning the subject matter of this article.


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Psychiatric Times This article originally appeared on:


APA Reference
Martin, L. (2010). Pathological Lying: Symptom or Disease?. Psych Central. Retrieved on April 16, 2014, from

    Last reviewed: By John M. Grohol, Psy.D. on 10 Nov 2010


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