Thus, lies are of different degrees and are told for various purposes and with differing frequencies. What, then, amounts to "pathological" lying, and what distinguishes the pathological liar from the person who just lies a lot? Dike and colleagues1 suggest that the diagnosis is made when the lying is persistent, pervasive, disproportionate, and not motivated primarily by reward or other external factors. They also suggest, however, that a key characteristic of pathological lying may be its compulsive nature, with pathological liars "unable to control their lying," although another term they use is "impulsive." In addition, they refer to other accounts that speculate on whether the pathological liar may be unaware that he is lying, although they point to evidence showing that, when challenged, the pathological liar admits to at least a partial recognition of his or her lies (which assumes, of course, that pathological liars can be accurately identified so this can be tested in the absence of a clear definition or operational criteria).....snippet from above link.
