Cotard syndrome is a specific nihilistic delusion named after Jules Cotard, a French neurologist. Cotard first described the condition in 1880, which he called le délire de négation (negation delirium). The affected individual holds the delusional belief that he or she is already dead, does not exist, is putrefying, or has lost their blood or internal organs.
Very few patients with Cotard syndrome have been reported, but a recent case study displayed a correlation between Cotard syndrome and valacyclovir toxicity. A 55-year-old woman who had been treated for shingles with the antiviral medication valacyclovir displayed a change in mental status. She began to dance and laugh, shouting out "I am in Heaven," believing that she had died. After undergoing hemodialysis for 3 days, she returned to baseline and no longer showed any signs of Cotard syndrome.
Reduplicative paramnesia consists of the delusional belief that a place or location has been duplicated. This belief can be that a location exists in two or more places simultaneously, or that it has been relocated to another site. Reduplicative paramnesia is similar to Capgras syndrome; however, the individual believes in duplicates of a physical location rather than a person.
The term "reduplicative paramnesia" was first used by neurologist Arnold Pick in 1903. Pick was observing a patient with suspected Alzheimer disease who believed that she was being treated in a replica of the clinic in her hometown. The patient held her convictions of the hospital being a duplicate steadfastly, even when Pick tried to rationalize with her.
Although little research on reduplicative paramnesia exists owing to the lack of case studies, a recent study on a 55-year-old man who believed he was in California and Texas at the same time has shifted the etiology of reduplicative paramnesia to be correlated with lesions in the right frontal lobe.
Alien Hand Syndrome
Alien hand syndrome is the belief that your hand does not belong to you, but rather has a life of its own. The afflicted person has normal sensation but believes that the hand, while still being a part of their body, is acting autonomously, having a will of its own. In effect, afflicted people have lost the sense of agency associated with purposeful movement of the hand while retaining a sense of ownership of it.
Persons with this syndrome will often personify the alien hand, believing it to be "possessed" by some spirit or an entity that they may name or identify. There is a clear distinction between the behaviors of the two hands, in which the affected hand is viewed as "wayward," whereas the unaffected hand is under normal volitional control.
At times, particularly in patients who have sustained damage to the corpus callosum that connects the two cerebral hemispheres, the hands appear to be acting in opposition to each other; this phenomenon has been termed "intermanual conflict" or "ideomotor apraxia." Alien hand syndrome is usually caused by stroke or other brain damage, specifically in the regions surrounding the corpus callosum, frontal lobe, or parietal lobe.
A recent case of alien hand syndrome was found in a 65-year-old professional pianist. When the subject turned 60 years old, she started to experience involuntary movement of her right hand while practicing piano. She described her hand as having "an entity of its own." After an MRI was completed, it was revealed that the subject had severe atrophy in her left hemisphere and a disruption in the connections of corpus callosum fibers. This study has aided in achieving insight into the localization of lesions in motor centers that result in the sensation of strangeness of an alien limb.
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Cite this: Rare and Unusual Psychiatric Syndromes: A Primer - Medscape - Jul 23, 2018.