The habitual liar may wear a false smile, may lack head movement and use a number of filler words, such as "er" or "uh." Many pathological liars have other personality disorders or a mental illness.
With practice, it is often easy to recognize the signs that will let a person know they are in the presence of a pathological liar. Pathological liars may become such because of substance abuse, living in a dysfunctional family or because of neuropsychological abnormalities.
Pathological liars are often not aware of their habit to constantly lie. They lie to feel important because they are insecure, may feel bored or lie to simply get attention.
People who are pathological liars often change jobs frequently because their lies are discovered. They may get into new relationships easily, but when their partner discovers the constant lies, those relationships tend to go sour quickly. Pathological liars are also often estranged by family members who get tired of being that close to a person who always lies.
In order to stop the cycle of lying, a person should seek professional help from a qualified therapist. Families of pathological liars must set limits, especially if the liar will not seek help on his own.