While some data exist that point to nervous-system dysfunction in 40 percent of compulsive liars, and other research implicates deficiencies in intelligence or home-life stability as the probable causes, Forman argues these claims are mostly specious.
Pseudologia fantastica has not been reviewed in the English literature in over 50 years, but the term is still used, for example, among the diagnostic criteria for the Munchausen syndrome. Based upon a review of 72 cases of pseudologia fantastica collected from 26 reports since its initial description in 1891, pseudologia is distinguished from other types of lying. Pseudologia fantastica is typified by these characteristics: (1) the stories are not entirely improbable and are often built upon a matrix of truth; (2) the stories are enduring; (3) the stories are not told for personal profit per se and have a self-aggrandizing quality; and (4) they are distinct from delusions in that the person when confronted with facts can acknowledge these falsehoods. The authors compile phenomenological data about “the pseudolouge”, who is represented equally males and females. Intelligence varies, but at least 40% have evidence of central nervous system dysfunction. The authors suggest that disease simulation, peregrination, and imposture are secondary behavioral manifestations of pseudologia, which is deserving of additional study.