Capgras Delusion

Capgras Delusion

The Capgras delusion theory (or Capgras syndrome) is a disorder in which a person holds a delusion that a friend, spouse, parent, or other close family member has been replaced by an identical-looking impostor. The Capgras delusion is classified as a delusional misidentification syndrome, a class of delusional beliefs that involves the misidentification of people, places, or objects. It can occur in acute, transient, or chronic forms. Cases in which patients hold the belief that time has been "warped" or "substituted" have also been reported.

The delusion is common in patients diagnosed with neurological disorders such as schizophrenia, brain injury and dementia. It presents more often in individuals with neurodegenerative diseases than in those without a coexisting neurodegenerative disease and tends to occur at an older age in the former compared to the latter. It has also been reported as occurring in association with diabetes, hypothyroidism and migraine attacks. It occurs more frequently in females, with a female:male ratio of 3:2. Although the Capgras delusion is commonly called a syndrome, because it can occur as part of, or alongside, various other disorders and conditions, some researchers have argued that it should be considered a symptom, rather than a syndrome or classification in its own right. In one isolated case, the Capgras delusion was induced in a healthy subject by the drug ketamine.