Abnormal P300 in a case of delusional misidentification with coinciding Capgras and Frégoli symptoms

Towards a unified, yet pluralistic, account of Capgras' delusion

INTRODUCTION

In this paper, we present a new way of thinking about what is going on in cases of Capgras delusion which is a more varied presentation than represented in the literature. We do this by reflecting on the fundamental nature of identification, and then draw some lessons from this for understanding misidentification in general and Capgras delusion cases in particular. What emerges, through the conceptual tool of "mental files", is a unified, yet pluralistic, account of delusional misidentification of the Capgras type. In other words, it allows us to see the delusion for what it really is and to understand what all such instances have in common (hence unified), while also accommodating the great heterogeneity in cause, aetiology and clinical presentation (hence pluralistic).

METHODS

We apply the innovation of mental files and the idea that misidentification is fundamentally about file mismanagement to provide a better understanding of Capgras delusion.

RESULTS

We demonstrate how the mental files account allows us to more plausibly accommodate the variety of clinical cases that more traditional approaches fail to account for. It also points us in the direction of as-yet-undeveloped aetiological models.

CONCLUSIONS

The mental files approach provides us with a unified, yet flexible, framework, and as such furthers our understanding of misidentification and the Capgras delusion.

In fear of the most loved ones. A comprehensive review on Capgras misidentification phenomenon and case report involving attempted murder under Capgras syndrome in a relapse of a schizophrenia spectrum disorder

The present paper aims to describe a case of a schizophrenia spectrum disorder relapse leading to attempted murder, review literature, and investigate the epidemiological data and expression of violent behavior among Capgras-related incidents. 109 case reports deriving from various scientific areas dating from 1971 to 2017 were evaluated and juxtaposed with an equivalent comparison group of random psychiatry inpatients, who were examined for the same variables. Quantitative and qualitative differences were observed between samples. High level of interpersonal violence was disclosed among Capgras-related incidents, especially towards the main care-givers, with higher propensity among male patients. Homicidal behavior was also expressed in higher levels among male patients experiencing the Capgras delusion. A multidisciplinary approach is vital for the optimal management of these incidents. Further research on the pathophysiology of Capgras delusion with the utilization of functional imaging techniques is of exceptional significance for the understanding of issues of neuroscience.

An unusual delusion of duplication in a patient affected by Dementia with Lewy bodies

Background

Dementia with Lewy bodies (DLB) is the second most frequent diagnosis of progressive degenerative dementia in older people. Delusions are common features in DLB and, among them, Capgras syndrome represents the most frequent disturbance, characterized by the recurrent and transient belief that a familiar person, often a close family member or caregiver, has been replaced by an identical-looking imposter. However, other delusional conditions near to misidentification syndromes can occur in DLB patients and may represent a major psychiatric disorder, although rarely studied systematically.

Case presentation

We reported on a female patient affected by DLB who presented with an unusual delusion of duplication. Referring to the female professional caregiver engaged by her relatives for her care, the patient constantly described the presence of two different female persons, with a disorder framed in the context of a delusion of duplication.

A brain 99Tc-hexamethylpropyleneamineoxime SPECT was performed showing moderate hypoperfusion in both occipital lobes, and associated with marked decreased perfusion in parieto-fronto-temporal lobes bilaterally.

Conclusions

An occipital hypoperfusion was identified, although in association with a marked global decrease of perfusion in the remaining lobes. The role of posterior lobes is certainly important in all misidentification syndromes where a natural dissociation between recognition and identification is present. Moreover, the concomitant presence of severe attentional and executive deficits evocative for a frontal syndrome and the marked global decrease of perfusion in the remaining lobes at the SPECT scan also suggest a possible dysfunction in an abnormal connectivity between anterior and posterior areas.

Electronic supplementary material

The online version of this article (doi:10.1186/s12883-017-0842-1) contains supplementary material, which is available to authorized users.

fMRI functional connectivity of the periaqueductal gray in PTSD and its dissociative subtype

BACKGROUND

Posttraumatic stress disorder (PTSD) is associated with hyperarousal and active fight or flight defensive responses. By contrast, the dissociative subtype of PTSD, characterized by depersonalization and derealization symptoms, is frequently accompanied by additional passive or submissive defensive responses associated with autonomic blunting. Here, the periaqueductal gray (PAG) plays a central role in defensive responses, where the dorsolateral (DL-PAG) and ventrolateral PAG (VL-PAG) are thought to mediate active and passive defensive responses, respectively.

METHODS

We examined PAG subregion (dorsolateral and ventrolateral) resting-state functional connectivity in three groups: PTSD patients without the dissociative subtype (n = 60); PTSD patients with the dissociative subtype (n = 37); and healthy controls (n = 40) using a seed-based approach via PickAtlas and SPM12.

RESULTS

All PTSD patients showed extensive DL- and VL-PAG functional connectivity at rest with areas associated with emotional reactivity and defensive action as compared to controls (n = 40). Although all PTSD patients demonstrated DL-PAG functional connectivity with areas associated with initiation of active coping strategies and hyperarousal (e.g., dorsal anterior cingulate; anterior insula), only dissociative PTSD patients exhibited greater VL-PAG functional connectivity with brain regions linked to passive coping strategies and increased levels of depersonalization (e.g., temporoparietal junction; rolandic operculum).

CONCLUSIONS

These findings suggest greater defensive posturing in PTSD patients even at rest and demonstrate that those with the dissociative subtype show unique patterns of PAG functional connectivity when compared to those without the subtype. Taken together, these findings represent an important first step toward identifying neural and behavioral targets for therapeutic interventions that address defensive strategies in trauma-related disorders.

Capgras' syndrome in first-episode psychotic disorders

BACKGROUND

Misidentification phenomena, including the delusion of 'imposters' named after Joseph Capgras, occur in various major psychiatric and neurological disorders but have rarely been studied systematically in broad samples of modern patients. This study investigated the prevalence and correlated clinical factors of Capgras' phenomenon in a broad sample of patient-subjects with first-lifetime episodes of psychotic affective and nonaffective disorders.

METHODS

We evaluated 517 initially hospitalized, first-episode psychotic-disorder patients for the prevalence of Capgras' phenomenon and its association with DSM-IV-TR diagnoses including schizophreniform, brief psychotic, unspecified psychotic, delusional, and schizoaffective disorders, schizophrenia, bipolar-I disorder and major depression with psychotic features, and with characteristics of interest including antecedent psychiatric and neurological morbidity, onset type and presenting psychopathological phenomena, using standard bivariate and multivariate statistical methods.

RESULTS

Capgras' syndrome was identified in 73/517 (14.1%) patients (8.2-50% across diagnoses). Risk was greatest with acute or brief psychotic disorders (schizophreniform psychoses 50%, brief psychoses 34.8%, or unspecified psychoses 23.9%), intermediate in major depression (15%), schizophrenia (11.4%) and delusional disorder (11.1%), and lowest in bipolar-I (10.3%) and schizoaffective disorders (8.2%). Associated were somatosensory, olfactory and tactile hallucinations, Schneiderian (especially delusional perception), and cycloid features including polymorphous psychotic phenomena, rapidly shifting psychomotor and affective symptoms, pananxiety, ecstasy, overconcern with death, and perplexity or confusion, as well as rapid onset, but not sex, age, abuse history, dissociative features, or indications of neurological disorders.

CONCLUSIONS

Capgras' syndrome was prevalent across a broad spectrum of first-episode psychotic disorders, most often in acute psychoses of rapid onset.

Psychophysiological evidence for altered information processing in delusional misidentification syndromes

Recent research provides evidence that delusional misidentification syndromes (DMS) are associated with cognitive deficits. However, the underlying mechanisms of these deficits are not known. Since the P300 component of event-related potentials (ERPs) is related to fundamental aspects of working memory (WM), the present study is focused on P300 elicited during a WM test in DMS patients, as compared to those of healthy controls. Nine patients with DMS and 11 healthy controls, matched for age, sex and educational level were tested with a computerized version of the digit span test of the Wechsler batteries. Auditory ERPs were measured during the anticipatory period of the test. DMS patients showed significant reductions in P300 amplitude at the right frontal region compared to healthy controls. P300 latency in the central midline brain region was significantly prolonged in the DMS group. Each of these measures classified correctly 90% of the two groups. Moreover, the memory performance of the patient group was significantly lower, relatively to healthy controls. These findings provide evidence supporting the suggestion that DMS is associated with psychophysiological alterations occurring at the right frontal region, which mediates automatic processes, as well as with an irregular allocation of attentional resources, involving the interhemispheric circuitry, possibly due to gray matter degeneration. Finally, present work points to a need for further research investigating the characteristics, causes, course and treatment of severe cognitive deficits associated with DMS.