Capgras Syndrome and Other Delusional Misidentification Syndromes.

The delusional misidentification syndromes (DMS) are a group of disorders, characterized by patients mistaking the identity of people they know, although they recognize them physically. The term DMS is an umbrella term which may cover disorders whose definition extends to objects other than people, such as animals, places, or familiar material objects. The most common and best known DMS is Capgras syndrome. In this disorder, the misidentification leads to the delusional conviction that a close friend or relative has been replaced by an identical - or almost identical - "double," whose original has disappeared. This double is an imposter without name or identity. Most often considered as a persecutor, the double may be subjected to aggression, which may be very violent. Neuropsychological hypotheses based on cerebral dysfunctions are now commonly considered to be at the origin of the disorder. They have been elaborated from achievements in the neurosciences, particularly the facial recognition models. In return, knowledge about the normal cognitive processes involved in recognition and familiarity has benefited from the work that cognitive neuropsychiatry has invested in these disorders. The DMS are observed in various contexts of morbidity: primary psychiatric diagnosis, or secondary to various organic disorders, particularly in neurodegenerative disease; they are rarely met in isolated form. Most often, they develop in line with the associated pathology. In the absence of consensual clinical description, the epidemiology of DMS is uncertain; they may be more frequent than previously supposed. There is no specific treatment for these disorders; neuroleptics are generally used in association with treatment of the concomitant disorder. The frequent association of DMS with organic disorders which may be curable and the particularly dangerous profile of these patients are factors that underline the need for better screening.

[Pachydermatodactyly associated with plantar pachydermy]. / Pachydermodactylie associée à une pachydermie plantaire.

INTRODUCTION: Pachydermodactyly is a superficial fibromatosis located on the proximal portion of fingers'phalanges and interphalangeal joints. Several types of this disease have been described depending on topography, etiology and pathological associations. We report a typical observation of pachydermodactyly associated with a plantar pachydermy. CASE-REPORT: A 19 year-old man was followed for a psychotic disease, associated with mental retardation. On clinical examination, he showed a typical pachydermodactyly, predominantly located on the second, third and fourth fingers of both hands, associated with recent acrocyanosis. A pachydermic aspect was also observed on the external part of the feet sole. Histopathological analysis was identical on digital and plantar lesions with collagen swelling. These lesions extended into the subcutaneous fat only in the feet. DISCUSSION: This observation is compatible with the most classical form of pachydermodactyly which involves several fingers of both hands, usually in men. Furthermore, the association with a psychiatric disorder and the notion of repeated traumatisms have been frequently reported in the literature. However, acrocyanosis and the important disability observed in our case are unusual. Association with plantar pachydermy has never been reported. The identical histological aspect on finger and feet sole suggests that pachydermatodactyly should be integrated in framework of acral pachydermy.

[The French concept of "Athymhormie" (Loss of vital force) from 1922 to the present]. / Le concept français d'athymhormie de 1922 à nos jours.

The psychiatric concept of athymhormie (loss of vital force "élan vital" and affectivity) was developed at the beginning of the 20th century and used exclusively in France, until it was fortunately adopted by mostly French-speaking neurologists. The authors of the concept, M Dide and P Guiraud, considered the term an independent entity, an heir to dementia praecox, for which they did not like to substitute a "schizophrenia" with blurry boundaries. This term then came to mean to them, and to most French psychiatrists to this day, the basic core of psychosis' deficient forms. The word athymhormie (or loss of psychic self-activation) is now also used in neurology for the behavioural and emotional consequences of lesions caused on basal nuclei and, more widely, of a circuit associated with the limbic loop. However, the phenomenological reality of the associated disorders and the relevance of the same name can be questioned. This review concludes that although the settings--in a psychiatric or a neurologic clinic--where athymhormie takes place are very different, the choice of the same name is justified in a renewed and symptomatic neuropsychiatric approach. The objective of this approach is to explore why some symptoms, common or similar, could represent the lack of a physiological function, presumed here to be motivation.

Delusional misidentification syndromes.

The editors first describe the principal symptoms of the Capgras delusion, the Frégoli delusion, the delusion of intermetamorphosis and the delusion of subjective doubles before developing the argument that it would be appropriate for international psychiatric diagnostic systems to include these disorders. Furthermore the similarity between them, the reduplicative paramnesias and déjà and jamais vu are pointed out. By stressing a symptom-based approach it is possible to examine psychiatric, neurological and medical cases as arising from the same underlying disturbance in cognition function. The relationship between delusions of misidentification and other delusions is also touched upon.

Capgras syndrome: agnosia of identification and delusion of reduplication.

In the Capgras syndrome (CS) there is a natural dissociation between recognition and identification and it deserves to be designated as an agnosia of identification. Joseph Capgras who first introduced this concept of agnosia, also suggested that the syndrome might be studied within the framework of 'méconnaissance systématique' (translated here as systématic unawareness), thus anticipating a type of interpretation in which the basis of CS (and other delusional misidentification syndromes) would be a lack of corporeal and/or egocentric space awareness. From two examples, it is suggested that the basic phenomenon of unawareness may be due to sensory deprivation. A particular process of awareness concerning personal objects is hypothesized which would explain the specific delusion of reduplication that occurs when these objects are misidentified.

[Affective disorders and dementia of the frontal lobe type. Hypothesis of a pathogenic relationship]. / Troubles de l'humeur et démence de type frontal. Hypothèse d'un rapport pathogénique.

The evolution of some dysthymic states towards dementia is now rarely considered whereas it was well known at the beginning of the century. In French the final stage of this evolution was known as "démence vésanique". In recent years it has been noted that a proportion of patients with presenile dementia do not have Alzheimer's disease (AD) but a particular type of cognitive impairment., called dementia of the frontal lobe type (DFT), characterised by clinical and neuropsychological signs of frontal lobe disorder as well as an anterior defect of cerebral perfusion or metabolism. The onset of DFT is insiduous and marked by personality changes and inappropriate affect. It has not yet been reported as starting with true dysthymic disorders. PATIENTS AND METHODS. Ten right handed patients (F/M = 9/1) became dysthymic in their fifties (m = 49.8 + 7.6 yr). All initially met the DSM III-R criteria for mood disorders. They were all treated with the standard drugs or ECT. Although initially responsive all the patients relapsed and their dysthymic disorders became less typical in presentation. At a mean age of 63.6 +/- 2.9 yrs a particular type of dementia became evident. None of the patients had a previous history of mood disorder or a family history of dementia. The demented patients received thorough clinical examinations and 8/10 were tested with the Wechsler Adult Intelligence Scale (WAIS). All had XCT and HMPAO-SPECT scans using a rotating gamma camera. Three patients had a MRI Scan. RESULTS. The main symptoms were apathy and a lack of spontaneity as a result of which the patients were no longer able to live alone. HMPAO-SPECT: All the patients had clear hypoperfusion of the frontal and temporal lobes with seven showing a left predominance. XCT: A moderate degree of cortical atrophy, more pronounced in the frontal lobes, was observed in 6 patients. In 3 of them a previous XCT scan had been normal. MRI: Subcortical white matter hyperintensities were seen in the 3 patients examined. DISCUSSION. Although our patients do not probably form, with regard to a etiology a homogeneous group, they share common characteristics which are very similar to those which differentiates DFT from AD. We postulate that some dysthymic disorders of the presenium might represent the initial stage of this type of dementia. This hypothesis relies on the evidence for frontal dysregulation in mood disorders as demonstrated, for example, by PET studies. In these cases the cortical abnormalities usually disappear as the dysthymia improves and are considered functional phenomena. They may correspond to the mechanism of deafferentation (or diaschisis). This implies a primary lesion, presumably located at a subcortical level (for instance a white matter lesion) producing a disruption of function in a distant (initially) intact brain region. As a supplementary hypothesis we propose that with time, and for as yet unknown reasons, the frontal hypoperfusion in our patients lost its reversibility and that, as a result, a particular type of dementia became manifest. In some cases this diaschisis protractiva may lead to secondary cortical atrophy. CONCLUSIONS. A DFT was found in 10 patients who had become dysthymic in their fifties. A pathogenic hypothesis i.e. diaschisis protractiva, is proposed, based on the evidence of neuroimaging studies.

Recognition memory in psychotic patients.

Preliminary data are reported from experiments in which Warrington's (1984) Recognition Memory Tests were given to patients with misidentification delusions including the Capgras type and to psychotic patients. The results showed a profound impairment on face recognition for most groups, especially those with the Capgras delusion. It was rare to find a patent whose score on the word test was anything but normal.