also known as pseudologia, mythomania, compulsive lying or pathological lying – several of many terms applied by psychiatrists to the behaviour of habitual or compulsive lying in speech and writing. It was first described in the medical literature in 1891 by Anton Delbrueck. Although 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”. The individual may be aware they are lying, or may believe they are telling the truth, being unaware that they are relating fantasies.
The defining characteristics of pseudologia fantastica are:
1. The stories told are not entirely improbable and often have some element of truth. They are not a manifestation of delusion or some broader type of psychosis: upon confrontation, the teller can admit them to be untrue, even if unwillingly.
2. The fabricative tendency is long lasting; it is not provoked by the immediate situation or social pressure as much as it is an innate trait of the personality.
3. A definitely internal, not an external, motive for the behavior can be discerned clinically: e.g., long-lasting extortion or habitual spousal battery might cause a person to lie repeatedly, without the lying being a pathological symptom.
4. The stories told tend toward presenting the liar favourably. For example, the person might be presented as being fantastically brave, knowing or being related to many famous people.
Pseudologia fantastica may also present as false memory syndrome, where the sufferer genuinely believes that fictitious events have taken place, regardless that these events are fantasies. The sufferer may believe that he or she has committed superhuman acts of altruism and love or has committed equally grandiose acts of diabolical evil, for which the sufferer must atone, or has already atoned for in her/his fantasies.
[Usopp has this. Headcanon accepted? Headcanon accepted.]