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