The neuropsychological correlates of pathological lying: evidence from behavioral variant frontotemporal dementia

To assess the neuropsychological bases of deception in a case of pathological lying. Pathological lying describes a clinical picture in which an individual repeatedly and apparently compulsively tells false stories. Developmental studies and neuroimaging studies suggested that executive functions and Theory of Mind are necessary for deception and that a dysfunctional prefrontal cortex may be involved in pathological lying. A patient presenting a pattern of behavioral alterations, including pathological lying, underwent a neurological, neuroradiological, neuropsychiatric, and neuropsychological examination. Psychopathological symptoms and cognitive deficits (executive functions and Theory of Mind) were suggestive of a behavioral variant frontotemporal dementia (bvFTD), while the lack of prefrontal hypometabolism was suggestive of a bvFTD phenocopy syndrome. This first observation of pathological lying as a symptom of bvFTD contributes to characterize its spectrum of psychopathological features. Moreover, this clinical case contributed to describe the possible neurocognitive deficits involved in the development of pathological lying. Further studies are needed to investigate how a prefrontal impairment affecting executive functions and Theory of Mind may cause a susceptibility to pathological lying.