The Archives of Neurology indicates Capgras syndrome occurs when someone holds the delusional belief that a person has been replaced by an impostor or doppelgänger. A 2007 study of 38 cases reveals Capgras syndrome mainly happens in patients with Lewy body disease who are older than age 70. Younger patients around the age of 51 may see Capgras syndrome in conjunction with schizophrenia, methamphetamine abuse and schizoaffective disorder.
Those with Capgras syndrome believe people, typically close relatives, have been replaced by impostors. The delusional mind notices slight changes in appearance from the doppelgänger to the "real" person, according to the Archives of Neurology. Caregivers often find this situation difficult, but Psych Central explains three concepts to help the person with Capgras syndrome, which include entering the person's reality, never arguing with the person and creating positive emotional experiences.
Capgras syndrome, with Lewy body disease, is marked by visual hallucinations. Other brain or psychiatric disorders with Capgras syndrome may not reveal visual stimuli. The one factor among all patients was that the belief in impostors occurs with another brain disorder or psychiatric difficulty, according to the Archives of Neurology.
The syndrome is named after Joseph Capgras, the French psychiatrist who first noted the disorder. Psychiatrists originally believed the disorder was rare, but psychological literature and case studies reveal Capgras syndrome may be more prevalent than previously thought, according to Psych Central.