By the age of three or four, we all start to lie. At this point in our brain's development, we learn that we have an incredibly versatile and powerful tool at our disposal – our language – and we can use it to actually play with reality and affect the outcome of what's happening.

Sooner or later we learn that lying is "bad," and we shouldn't really do it. But if Jim Carey's "Liar Liar" taught us anything, it's that this just isn't feasible. We all have to lie sometimes.

But some people are pathological liars, meaning they can't stop spreading misinformation about themselves and others. The psychological reasons for why some people are this way is a bit of a mystery, but in the third edition of the Diagnostic and Statistical Manual of Mental Disorders, pathological lying is a disorder in its own right, as well as a symptom of personality disorders like psychopathy and narcissism.

"I think it comes from a defect in the neurological wiring in terms of what causes us to have compassion and empathy," psychiatrist Judith Orloff, author of The Empath's Survival Guide, told Business Insider.

"Because narcissists, sociopaths, and psychopaths have what's called empathy deficient disorder, meaning they don't feel empathy in the way we would."

The truth doesn't matter to narcissists

When you don't care about other people, lies don't seem to matter. A lack of empathy essentially means a lack of conscience, which is a hard concept to grasp for a lot of people.

"When they lie it doesn't hurt them in the same way it would hurt us," Orloff said.

"So many people get into relationships with pathological liars, or just can't understand why they're lying, because they're trying to fit these people into the ordinary standards of what it means to be empathetic."

But they don't fit. In fact, they may not even realise they are lying half the time, because they're not conscious of it. Orloff said they actually believe they are telling the truth a lot of the time. It's not so much about the fact itself, she said, as it is about wanting to have power over somebody.

This is extremely dangerous for highly sensitive people, becuase they attract narcissists. Then when they see someone is lying, they try and figure it out, or blame themselves.

Once the lies start, it can end with the victim being gaslighted, which is essentially when they are told over and over again that their version of reality is incorrect, and they begin to believe the warped truth of the abuser.

"The great power of relationships is when you can tell the truth to one another, and trust each other, and be authentic – and with pathological liars you can't trust them," Orloff said.

"You can't base your life around them. It's like a moral deficit, and there's no accountability. Someone who is a pathological liar will not say I'm sorry for doing it. They will say it's your fault."

The only way to escape the clutches of a pathological liar is to be strong enough to say "no this is not my fault, this is not ringing true to me, so I can't really trust you," she said.

Unfortunately, people tend to doubt themselves, because the lies can escalate subtly. It may start with a small white lie, and a few months later the victim's life with be a mess of confusion because of the web of tall tales that has been woven.

"If somebody lies, don't try and make an excuse about it," Orloff said.

"A lie is a lie. And if you bring it up to the person and they say it's your fault, or no it didn't happen, just know there's something very wrong going on."

Compulsive liars are not necessarily bad people

Psychologist Linda Blair, an author of many psychology books, told Business Insider some compulsive liars are simply too impulsive to tell the truth.

The impulsive-reflective scale is ingrained in our genes, and it's very hard for someone highly impulsive to take the time to think things through, just as it is a challenge for a reflective person to jump into something head first.

"If you're an impulsive person, it's really hard to break the habit, because you have this terrible feeling inside you that you have to sort things out right now," Blair said.

"So when it comes to your head, you just say it. That doesn't mean you necessarily lie, but it's a little harder for you to stop from lying, more than it is for someone who's more reflective."

Pathological lying and narcissism aren't synonymous, they just sometimes go hand in hand. In other cases, compulsive liars just might not have the capacity to stop themselves blurting things out. And Blair said they just need to learn to control their urges and compulsions. Their lies don't necessarily come from a bad place.

"I don't think it's something they know how to deal with," she said.

"We think probably it has something to do with actual brain function and the way some people's brains work, which makes it much harder for them to understand the effect it will have on other people… We think, but we just don't know yet for sure."

This article was originally published by Business Insider.

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