[Treatment and Care for Elderly Patients with Dementia with Lewy Bodies Presenting with Delusional Misidentification Syndrome Including Capgras Syndrome: How to Respond and Intervene from a Neurologist's Perspective]

Aged patients with dementia with Lewy body (DLB) present with delusional misidentification syndrome and occasionally Capgras' syndrome. It is difficult to treat the DLB patients presenting with these psychiatric symptoms, as well as dementia, parkinsonism, sleep disorders, and autonomic dysfunction. In advanced stage of DLB, it is necessary to pay careful attentions to the appropriate choice of drugs as well as to improve the environment surrounding the DLB patients. At an earlier stage of DLB, before the exacerbation of illness, it is important to explain the clinical features and treatments of various symptoms for the patient, their family members, and caregivers.

Misidentification of self and the Riel Phenomenon

Misidentification syndromes or phenomena are found in a number of psychiatric situations that may become the subject of forensic science review. One of the most curious is misidentification of self in which the individual perceives himself or herself as another being while able to explain the loss of the original identity. Recognizing these phenomena may be helpful in accurate diagnosis, in considering such conditions as psychosis of whatever type, multiple personality disorder, and other amnesia and fugue states, and in understanding the person's psychopathology. Two cases are presented to illustrate a process that the authors have named the Riel Phenomenon, after the person who was a party to what is often recognized as the most famous case in Canadian history.

Misidentified political figures: an underappreciated danger

A series of twelve patients is presented in which each patient suffered from one or more misidentification syndromes and also misidentified one or more political figures. The fact that misidentification syndromes have been associated with physical violence and that the majority of the patients studied had a history of physical violence suggests that these individuals could pose a significant danger of physical harm to others, including political figures. Persons who threaten political figures should be evaluated for misidentification syndromes.

The syndrome of Capgras

Three new cases of the syndrome of Capgras are presented. An unusual variant of the syndrome is recorded. It is contended that the definition of the syndrome should be widened to include impersonators who exhibit slight differences from the prototype, and that ambivalence and projection cannot explain all cases. The syndrome is critically reviewed.