Pathological lying

Pathological lying, also known as mythomania and pseudologia fantastica, is a mental disorder in which the person habitually or compulsively lies.
It was first described in the medical literature in 1895 by . Although it is a controversial topic, pathological lying has been defined as "falsification entirely disproportionate to any discernible end in view, may be extensive and very complicated, and may manifest over a period of years or even a lifetime".
Characteristics.
Defining characteristics of pathological lying include 
Some psychiatrists distinguish compulsive from pathological lying, while others consider them equivalent; yet others deny the existence of compulsive lying altogether; this remains an area of considerable controversy.
Diagnosis.
Pathological lying is listed in the "Diagnostic and Statistical Manual of Mental Disorders", although only as a symptom of other disorders such as psychopathy and antisocial, narcissistic, and histrionic personality disorders, not as a stand-alone diagnosis. The ICD-10 disorder Haltlose personality disorder is strongly tied to pathological lying.
It has been shown through lie detector tests that PF ("pseudologia fantastica") patients exhibit arousal, stress, and guilt from their deception. This is different from psychopaths, who experience none of those reactions. People affected by antisocial disorder lie for external personal profit in the forms of money, sex, and power. PF is strictly internal. The difference between borderline personality disorder (BPD) and PF is that BPD patients desperately try to cope with their feeling of abandonment, mistreatment, or rejection by making empty threats of suicide or false accusations of abandonment. Pathological liars do not feel rejected; they have high levels of self-assurance that help them lie successfully. Unlike those with histrionic personality, pathological liars are more verbally dramatic than sexually flamboyant. Narcissists think they have achieved perfection and are unempathetic to others. PF patients do not show these anti-social behaviors; they often lie because they think their life is not interesting enough.
The only diagnosis in the current system where purposeless, internally motivated deception is listed is axis I factitious disorder. This diagnosis deals with people who lie about having physical or psychological disorders (research must be done to confirm the individual does not in fact have a disorder. This may become troublesome due to the fact that medical records are sealed to the public). People with PF tend to lie about their identities and past history. Since the symptoms do not match up, the individual may go undiagnosed. Though they could well be diagnosed under the catch-all rubric of unspecified personality disorder (UPD) (ICD-10 code F69) or perhaps even under ICD-10 code F68.8 "Other specified disorder of adult personality and behaviour" as this defines itself as "This category should be used for coding any specified disorder of adult personality and behaviour that cannot be classified under any one of the preceding headings". Here the specified disorder is the lying for psychological reasons (not material ones e.g. sexual self-gratification etc.) and the behavior would also need to meet the necessary conditions to be viewed as a psychiatric illness.
Psychopathy.
Pathological lying is in Factor 1 of the Psychopathy Checklist (PCL).
Pathological liars.
Lying is the act of both knowingly and intentionally or willfully making a false statement. Normal lies are defensive and are told to avoid the consequences of truth telling. They are often white lies that spare another's feelings, reflect a pro-social attitude, and make civilized human contact possible. Pathological lying can be described as a habituation of lying. It is when an individual consistently lies for no personal gain.
There are many consequences of being a pathological liar. Due to lack of trust, most pathological liars' relationships and friendships fail. If this continues to progress, lying could become so severe as to cause legal problems, including, but not limited to, fraud.
Epidemiology.
The average age of onset is 21 years when the level of intelligence is average or above average. Sufferers have also shown above average verbal skills as opposed to performance abilities. Thirty percent of subjects had a chaotic home environment, where a parent or other family member had a mental disturbance. Its occurrence was found by the study to be equal in women and men. Forty percent of cases reported central nervous system abnormality such as epilepsy, abnormal EEG findings, ADHD, head trauma, or CNS infection.