As of 2015, there is no consensus about the psychology behind chronic lying, reports Psychiatric Times. Called pathological lying or pseudologia phantastica, the behavior differs from normal lying because the person telling the lies does it frequently and gains little benefit from the behavior. The lies are elaborate, fantastic in nature and sometimes even worsen the person's situation. However, experts argue over whether this behavior constitutes an illness in its own right or if it is secondary to another disorder.
Research about the epidemiology of pathological lying is sparse, which makes it difficult to reconcile the argument, notes Psychiatric Times. One study suggests that the condition surfaces between the ages of 16 and 22, that its incidence is equally common among males and females, and that it is present in perhaps 1 percent of juvenile offenders. People displaying this behavior score average or slightly below average on IQ tests but display markedly better verbal intelligence than high-performance IQ scores. Forty percent of the subjects in this study present with some history of abnormality, illness or injury in the central nervous system.
One problem that further complicates the argument about the nature of this behavior is the debate about whether the person telling the lies understands that he is lying, explains Psychiatric Times. Such people typically display sound judgment in other areas but often believe at least part of the lies and seem incapable of controlling the behavior, despite recognizing the potential harm to reputation and livelihood. There is also some difficulty in differentiating between pathological lying and other forms of dissimulation present in some psychiatric disorders.