Characterized as a delusional misidentification syndrome, reduplicative paramnesia is the delusional belief that a place or location has been duplicated and now exists in two or more places simultaneously. Although it is rare, it is most often associated with brain injuries, particularly when the right cerebral hemisphere and both frontal lobes are damaged simultaneously.
In 1903, psychiatrist Arnold Pick discovered a patient whom he suspected had Alzheimer’s disease, but was constantly insisting that she be moved to Pick’s city clinic, one that she claimed looked identical and was in a familiar suburb. In order to explain the discrepancies, she further claimed that Pick and his medical staff worked at both locations. This instance was the first time that the term “reduplicative paramnesia” was used.
It was, however, first discovered in 1788 by Swiss naturalist Charles Bonnet, who described a woman who had also had Cotard delusion, and by Henry Head, Paterson, and Zangwill who reported soldiers who had the delusional belief that their hospital was located in their hometown.
As stated before, reduplicative paramnesia is most commonly associated with head trauma, it has also been reported in association with a number of different neurological disorders including strokes, intracerebral hemorrhage, tumors, dementia, encephalopathy, and various psychiatric disorders. An example of this is a patient that suffered a head injury that resulted in a fractured skull and frontal lobe damage to both sides (more prominently in the right side), owing to the formation of intracerebral hematomas. He suffered no memory loss, but exhibited disorientation when it came to place. When he learned that he was in the Jamaica Plains Veterans Hospital in Boston, Massachusetts, he insisted that the hospital was located in Taunton, Massachusetts, and when he was questioned about it, he admitted that it was strange that there was more than one Jamaica Plains Veterans Hospital. This illusory relocation of a familiar place is a common theme in people who suffer from this disorder, although in some cases, the patient believes that they are in more fantastical or exotic locations.
Early explanations for this disorder suggested that it arose from a motivated denial of illness, as opposed to it being caused by a brain injury or trauma. The disorientation was also said to be caused by a hysterical reaction motivated by a desire to return home. Most modern theories, however, suggest that it is caused by a disruption of brain systems that are involved in memory and familiarity. It has also been said that damage to the right hemisphere of the brain was what caused the disorientation owing to the impaired visuospatial perception and visual memory, while frontal lobe damage was associated with the false impressions that were caused by the disorientation.
A more refined explanation suggests that damage to the ventral stream of the visual system, that connects the visual cortex to areas in the temporal lobes, could produce the required visuospatial disorientation and poor memory integration. The temporal lobes, including the hippocampus, are known to strongly interact with the frontal lobes during memory formation and retrieval, suggesting an explanation for why frontal damage could also lead to reduplicative paramnesia.