A psychological condition, otherwise known as pathological or compulsive lying, in which the sufferer habitually lies. The lies are caused by an internal need to lie, not environmental or social factors. Unlike in psychotic or delusional disorders, people with this condition can recognize they are lying, though they may be unwilling to do it, leading to anger, confusion, and (in some cases) violence following confrontation.
My friend has a terrible case of pseudologia fantastica. She says she's had ten different kinds of cancers, but she's never even been inside a hospital.
A severe psychological condition, similar to pathological lying, but different in the sense that the person afflicted genuinely believes their own lies. A person suffering from PF will often respond with anger, confusion and even violence when confronted about the truth of their statements.
Someone with PF may believe that they have written a movie script that is going to be filmed in Hollywood next weekend, and will tell their friends this lie every weekend for months.