Psychiatric doppelganger phenomena with special consideration of the Capgras syndrome]

The present paper classifies and analyzes the experience of the "double" in depth. Main focus is on the Capgras experience--certainly the best known phenomenon of the double--and its possible etiology is examined. Moreover, a few other delusional experiences of mis-identification of person are also considered, such as the Frégoli phenomenon, the syndrome of subjective doubles, intermetamorphosis as well as other variants described in the literature.     

The Capgras syndrome

A new case of Capgras' syndrome is presented with a short review on the subject. Since there are many controversies about the etiology of this syndrome, and since some authors explain it with organic factors, others with psychodynamic factors, or a combination of the two, one should be careful with this syndrome to eliminate the presence of organic factors with a meticulous physical examination and appropriate neuropsychological tests. A thorough examination of early interpersonal relations is necessary to verify psychodynamic hypothesis, the most plausible being the splitting of internalized object representations.     

A zoocentric Capgras syndrome

Capgras syndrome is a delusional misidentification, a phenomenon where a person believes delusionally that another person (in most cases closely related) has been replaced by a double or impostor of identical appearance. It is usually a symptom of a functional psychosis but sometimes it is also associated with organic cerebral dysfunction. We present a case of a 23-year old women who had the delusional belief that her cat had been replaced by the cat of her former boy-friend. Reviewing the literature we found that such a case is very rare. The association between Capgras syndrome and depersonalisation-derealisation phenomena is also pointed out.     

Delusional misidentification secondary to perceptual abnormality: An unusual case of Capgras syndrome

Capgras syndrome is the commonest of the delusional misidentification syndromes, occurring in 1 &#45 5% of psychotic patients. This case of a Capgras syndrome was secondary to an abnormal percept (auditory hallucination). Capgras syndrome is not a symptom specific to abnormalities of face recognition. ( Int J Psych Clin Pract 2000; 4: )     

An unusual case of Capgras syndrome: the psychiatric ward as a stage

A 31-year-old male psychiatric patient presented with an unusual multifaceted delusion of misidentification including Capgras syndrome, in which people in the immediate environment, the other patients and hospital staff, were seen as hired actors in a stage production. The genesis and reinforcement of his delusional thinking appears to be the results of psychological, organic, and ecological factors.     

Capgras syndrome with subarachnoid hemorrhage

Capgras misidentification syndrome after subarachnoid hemorrhage and the surgical repair of a right middle cerebral artery aneurysm is described. This Capgras delusional belief in an imposter assuming the form of a familiar person may result from disruption of cortical-visual-limbic pathways in the right hemisphere.     

Coexisting Diogenes and Capgras syndromes

The co-occurrence of Diogenes and Capgras syndromes, both unusual in themselves, would be expected to be rare. A MEDLINE search using the terms Diogenes, Capgras, self-neglect and domestic squalor revealed no previous reports of this combination of disorders. Both conditions are somewhat dubiously named as &#164 syndromes' when in fact they are probably no more than symptoms with different causes. Of particular interest in this case is the exacerbation of the self-neglect, characteristic of the Diogenes syndrome, by the delusional misidentification which marks the Capgras syndrome; as well as the reinforcement of the previously recognised association with frontal lobe pathology. The role of medication, though limited, is described. ( Int J Psych Clin Pract 2001; 5:75-76)     

Capgras syndrome in adolescence.

Capgras syndrome, the delusion of substitution, has rarely been reported in adolescents. The etiology is unknown, and intense controversy surrounds the debate over the relative importance of biological versus psychological factors. Presented here are two cases of Capgras syndrome in adolescents and a review of the relevant biological, neuropsychological, and psychodynamic literature. The authors suggest that the psychological processes underlying the Capgras delusion are mediated by neuroanatomical connections between various brain areas and hypothesize that the fundamental lesion in Capgras syndrome may be the patient's inability or failure to acknowledge the authenticity of a person they clearly recognize.     

Capgras syndrome-a biochemical marker?

Two cased of Capgras syndrome are reported in which platelet monoamine oxidase (MAO) activity is singificantly less than that of 24 psychiatric controls and 39 nonpsychiatric controls. This is the first report of a consistent biochemical abnormality associated with the Capgras phenomenon. Additional evidence is discussed which suggests that psychiatric patients with Capgras syndrome may belong to a discrete group of behavioral disorders characterized by reduced platelet MAO activity.