Syndromes of delusional misidentification consist of disordered familiarity and 
have been reported in diverse diagnoses, including Parkinson's disease. Although 
the most common delusional misidentification is Capgras syndrome, in which the 
sufferer believes a familiar person has been replaced by an identical imposter, 
other forms have been also described. The pathogenesis of delusions of 
misidentification appears to require dysfunction of or connection to a left 
cerebral cortical area involved in recognition of familiarity, and also right 
frontal cortex serving belief evaluation. Two cases of Parkinson's disease with 
an unusual delusional misidentification, intermetamorphosis, are presented, 
along with their improvement with pimavanserin, a novel atypical antipsychotic 
medication.