Mythomaniacs

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 well-intentioned you might be, this will probably not be effective. It is 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 and don't value the truth. If you question them on a lie and they are backed into a corner they will act very defensively.
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 whoever is in their favour at the moment.
5. 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?).