Pathological liars - or "mythomaniacs" - may be suffering from histrionic personality disorder or narcissistic personality disorder. The following comments basically reflect a pathological liar who has the characteristics of histrionic personality disorder.
Some characteristics
1. Exaggerates things that are ridiculous.
2. One-upping. Whatever you do, this person can do it better. You will never top them in their own mind, because they have a concerted need to be better than everyone else. This also applies to being right. If you try to confront an individual like this, no matter how lovingly and well-intentioned you might be - this will probably not be effective. It's threatening their fantasy of themselves, so they would rather argue with you and bring out the sharp knives than admit that there's anything wrong with them.
3. They "construct" a reality around themselves. They don't value the truth, especially if they don't see it as hurting anyone. If you call them on a lie and they are backed into a corner, they will act very defensively and say ugly things (most likely but depends on personality), but they may eventually start to act like, "Well, what's the difference? You're making a big deal out of nothing!" (again, to refocus the conversation to your wrongdoing instead of theirs).
4. Because these people don't value honesty, a lot of times they will not value loyalty. So watch what you tell them. They will not only tell others, but they will embellish to make you look worse. Their loyalty is fleeting, and because they are insecure people, they will find solace in confiding to whomever is in their favor at the moment.
5. They may be somewhat of a hypochondriac. This can come in especially useful when caught in a lie, for example, they can claim that they have been sick, or that there's some mysteriously "illness" that has them all stressed out. It's another excuse tool for their behavior.
6. Obviously, they will contradict what they say. This will become very clear over time. They usually aren't smart enough to keep track of so many lies (who would be?).
Another WikiAnswers contributor adds:
•They lie about even the smallest things. For example, saying "I brushed my teeth today," when they didn't.
•They add exaggerations to every sentence.
•They change their story all the time.
•They act very defensively when you question their statements.
•They believe what they say is true, when everyone else knows it isn't.
An alternate 'checklist':
•Lies when it is very easy to tell the truth.
•Lies to get sympathy, to look better, to save their butt, etc.
•Fools people at first but once they get to know him, no one believes anything they ever say.
•May have a personality disorder.
•Extremely manipulative.
•Has been caught in lies repeatedly.
•Never fesses up to the lies.
•Is a legend in their own mind.
More opinions and input from WikiAnswers contributors:
•I have found a few differences in pathological liar and a "slime ball" liar. Pathological liars cannot tell that they are lying; they actually believe the lie as soon as it comes out of their mouth. They lie about unimportant things that don't really matter to anyone. This can be caused by mental defect but isn't always. Slime-ball liars lie about things that make them look better or embellish to get attention. They also lie to keep their butts out of trouble and to get what they want.
•Here are things to ask yourself: How could this many things happen to one person? Would believe these stories if someone else told you? Think back to the beginning: you had red flags and alarms going off in you head. Learn to trust your instincts.
•It is very hard to tell when one is a pathological liar. Some people just are liars and lie to lie because they can and they don't care about getting caught and aware that you know they have lied. These people care not about lying, it's no big deal. It's like "ok, so what? I lied". The pathological liar on the other hand, IS aware that they are lying BUT will go to extremes to make you believe that they are truthful. They appear to believe their own lies BUT in truth, they know their lies are just that, lies. But because their efforts are constantly backing up their lies, it appears to us that they actually believe their lies, when we eventually do find out about them and then we tend to feel sorry for these people. Then they have an excuse, "I am sick, I don't know why I lie, I believed what I was saying etc." The only truth was the fact that they don't know why they lie. Other than that it's crap. It is true that most of them have an extremely low sense of self worth and are continuously trying to make themselves feel better about THEMSELVES and this is one reason they lie. It is about them but the lies are not always set up with the purpose to hurt some one else; it's that these people feel so low about themselves they need to create ANYTHING different from the ugly reality they feel about themselves so they lie about even the most tiniest little thing. The people closest to them get sucked into these lies which sometimes start as something very trivial and then turn into something that can turn everyone involved worlds upside down and inside out.
•Unmasking the pathological liar is an easier task when the pathological liar is no more than a casual acquaintence to the "un-masker." Close relationships provide camouflage for the pathological liar, and intimacy provides a heavily-fortressed breeding ground.
•Other indicators: 1) Rage attacks after they realize you're questioning their lies. 2) Distraction techniques, e.g. hanging up the phone when you catch them in lie, playing word games, or even just running out of the room. After using the distraction technique, or rage attack, or sometimes both, they will pretend that nothing ever happened. They re-write history, so it never did happen in their minds. Normal people do it too, but these people take it to the extreme.
•From "Go Ask Alice": Lies are unplanned and impulsive. Behavior is repeated over a long period of time. Lies don't seem to exist for any external reason. Behavior may not always be a conscious act. Lies are admitted, changed, and/or adapted if a false story is challenged.
•From Andrea Broadbent "The Truth about Truman": To begin, the definition of pathological actually means abnormal or grossly atypical. Therefore, a pathological liar prevaricates more frequently than the average person or tells more abnormal lies. In most cases, pathological liars tell lies that are "unplanned and impulsive" (Hausman). These lies are usually very emotional stories that tend to serve no purpose except to impress people (Ford 133). As of now, psychiatrists are unsure whether or not pathological liars are fully capable of realizing if and when they are lying, so detecting whether or not a person is a pathological liar is a very difficult task (Hausman). By looking at the list of conditions commonly connected with people considered to be pathological liars, psychiatrists are better able to determine whether or not a person might actually have the disorder. Some main qualities linked with pathological liars include dysfunctional family origin, family lying patterns, anomalies of sexual life, frequent substance abuse, and a great capacity for language.
•From Raymond Lloyd Richmond, Ph.D. "Psychological Honesty": Even a pathological liar carries deep in his heart a desire for goodness and honesty and yet, because of painful emotional wounds, believes that the world never has, and never will, recognize his pain. And so, to hide that pain from himself, he uses all the lies he can concoct to hurl at the world as he runs in fear from his own goodness.
•For me, the first indication has been that I hear them tell different things to different people and they can't all be right, because they directly contradict each other! And I am able to prove it. If you can prove over and over again that things someone is telling you are outright false, then you have a pathological liar on your hands.
With the Internet, it is now easier than ever to "fact-check" even the most mundane things. I think pathological liars often lose track of the lies they tell different people and it will eventually catch up with them.
Read more: http://wiki.answers.com/Q/How_can_you_tell_if_someone_is_a_pathological_liar#ixzz1EwgEFdXO
