Truth be told, we all lie sometimes. Ninety percent of our deceptions are white lies told to protect ourselves, to avoid getting into trouble, and to spare someone else’s feelings. For the most part, the lies we tell are motivated by an external reason. They are typically defensive to avoid the consequences of truth-telling—"I swear I have no idea what happened to that plate of cookies.” They may be tactical—“I never received your email” or altruistic —“You look great in that dress.”

Lying may be an integral part of our daily lives, but there is a big difference between “normal” lying and pathological lying, also known as pseudologia fantastica. The term pseudologia fantastica (PF) was first coined by the German physician, Anton Delbrueck, in 1891 to describe the phenomenology of a group of patients who told lies that were obviously extreme and fantastical with a clear departure from reality to the observer, yet perceived by the patients themselves as within the realm of possibility. People with PF lie about everything constantly, eloquently, excessively, and chronically.

These individuals “indulge in a veritable orgy of lying” to serve an ego-driven, internally motivated longing for how they wish the world would be and would see them. For instance, if your neighbor has a dilapidated but cherished old car and asks your opinion about it, you might stretch the truth and say something along the lines of, “I think your car is fabulous.” However, someone with PF would respond, “I have 10 vintage sports cars, all in top condition, at my large, private estate in Monaco.” The person with PF lies to self-aggrandize, not to flatter the neighbor.

Moreover, unlike cons who lie for external gain or profit, people with PF tell lies that go above and beyond what would be necessary to pull off a successful swindle. They are out of proportion to any obvious external reward. The lies they tell are “almost always dazzling or fantastical,” and easily roll off their tongue. Sometimes they lie “just because.” Lying is inherently gratifying for them. These are the people who lie about what they ate for lunch.

While there is no current gold-standard definition of pseudologia fantastica, several key characteristics have been identified:

1. They chronically tell lies or untrue stories that are unrelated to, or out of proportion to, any clear, objective benefit.
2. Qualitatively, the stories are dramatic, detailed, complicated, colorful, and fantastic.

3. The stories typically feature the pseudologue as the hero or victim and seem geared to achieve acceptance, admiration, and sympathy;

4. I terms of insight, the pseudologue lies somewhere along a spectrum between conscious deceit and delusion, not always conscious of his motives and seeming at least intermittently to believe his stories yet never to reach the level of conviction that would indicate a loss of reality-testing.

Most people are mortified and ashamed when their lies are exposed but not those with PF. When confronted with their deception , people with PF are typically unfazed. They don’t break out in hives or lose sleep or sweat. Rather, they double down, sometimes providing further elaborate details to explain the lies.

That said, in the face of incontrovertible evidence, they will—reluctantly —relinquish their tall tales. This stands in contrast to people with a delusional disorder who cling to their fixed false beliefs no matter what. PF often overlaps with borderline, antisocial, and narcissistic personality disorders , but not always. Sometimes they are stand-alone liars.

Confronting the person with their deceptions will likely backfire. As tempting as it is to take a prosecutorial approach and attempt to extract a mea culpa from the individual, save your breath. Exposure and questioning tend to stimulate further fabrication and evasion.

In a clinical setting, there is evidence that showing disinterest in the tales but maintaining interest in the person may help reduce the motivation to lie. While there is no guarantee of successful treatment, I think we can all agree that these people belong in a therapist’s office and not in political office.