The Capgras delusion is a rare disorder in which a person holds a delusional belief that an acquaintance, a spouse, sibling or parent has been replaced by an impostor with an identical appearance. Interestingly, some patients start to refer to themselves as two separate people; the real ‘me’ and the other ‘me’. This delusional misidentification syndrome is most frequently present in patients with paranoid schizophrenia, but has also been identified in patients with dementia, and those suffering from brain injuries. There is also speculation that the syndrome is associated with diabetes, hypothyroidism and migraines and in one instance it was even induced as a test using ketamine.
One case report described a patient with Capgras Delusion with the following: “Fred, a 59-year-old man with a high school qualification, was referred for neurological and neuropsychological evaluation because of cognitive and behavioural disturbances. He had worked as the head of a small unit devoted to energy research until a few months before. His past medical and psychiatric history was uneventful. […] Fred’s wife reported that about 15 months from onset he began to see her as a “double” (her words). The first episode occurred one day when, after coming home, Fred asked her where Wilma was. On her surprised answer that she was right there, he firmly denied that she was his wife Wilma, whom he “knew very well as his sons’ mother”, and went on plainly commenting that Wilma had probably gone out and would come back later.” Treatment for the Capgras delusion is usually a combination of individualised therapy and antipsychotic medication.