The delusional misidentification syndromes: strange, fascinating, and instructive

Parkinson disease psychosis: from phenomenology to neurobiological mechanisms

Parkinson disease (PD) psychosis (PDP) is a spectrum of illusions, hallucinations and delusions that are associated with PD throughout its disease course. Psychotic phenomena can manifest from the earliest stages of PD and might follow a continuum from minor hallucinations to structured hallucinations and delusions. Initially, PDP was considered to be a complication associated with dopaminergic drug use. However, subsequent research has provided evidence that PDP arises from the progression of brain alterations caused by PD itself, coupled with the use of dopaminergic drugs. The combined dysfunction of attentional control systems, sensory processing, limbic structures, the default mode network and thalamocortical connections provides a conceptual framework to explain how new incoming stimuli are incorrectly categorized, and how aberrant hierarchical predictive processing can produce false percepts that intrude into the stream of consciousness. The past decade has seen the publication of new data on the phenomenology and neurobiological basis of PDP from the initial stages of the disease, as well as the neurotransmitter systems involved in PDP initiation and progression. In this Review, we discuss the latest clinical, neuroimaging and neurochemical evidence that could aid early identification of psychotic phenomena in PD and inform the discovery of new therapeutic targets and strategies.

Coexistence of different delusional misidentification syndromes in clinical practice: A case series

OBJECTIVE

The objective of this study is to analyse the coexistence of several delusional misidentification syndromes in a clinical sample.

METHODS

Over one year, a sample of six patients presenting two or more types of delusional misidentification syndromes was selected. All these patients were admitted to the psychiatric inpatient unit of a Spanish hospital.

RESULTS

Despite the different diagnoses, the patients included presented different types of delusional misidentification syndromes, both hyperidentification and hypoidentification. Antipsychotic treatment was not very effective against these delusional misidentification syndromes.

CONCLUSIONS

The coexistence of several delusional misidentification syndromes indicates that the aetiopathogenesis of the different types is similar. It is a field with important clinical implications, due to the poor response to treatment, as well as the possible medico-legal implications.

The Doppelgänger phenomenon and death: a peculiar case of homicide by a subject with first-episode psychosis

The Doppelgänger phenomenon refers to the experience of a direct encounter with one's self, characteriswed by: (i) the perception of a figure with one's own identical physical features; or (ii) the apprehension that the perceived figure shares the same personality and identity. The Doppelgänger does not only look like the same person, it is his/her double. The perceptual element is usually a hallucination, although occasionally a false perception of an actual figure may be involved. This phenomenon has been described in individuals suffering from overwhelming fear, severe anxiety or intoxication, epilepsy, as well as in the sleep-wakefulness transition. It has also been reported in major psychoses. The fear of imminent death often precedes the Doppelgänger experience. This report presents the case of a 30-year-old man, Mr. Y, who was stabbed to death by Mr. X, his "double". The aggressor and his victim, although not related, were truly doubles; remarkably, they shared the same name and surname, age, professional activity and place of work. Moreover, they attended the same sports center but barely knew each other. The forensic psychiatric evaluations in Mr. X, subsequent to the crime committed, were suggestive of a psychotic condition. This case is unique in the scientific literature. In the most serious psychotic forms, the issue of the "double" calls into question not only the dissociative processes involved in the etiopathogenesis of the disorder, but also bio-psycho-social elements, as well as personal data in this case, which made the victim and the aggressor "identical". In the context of psychopathological functioning, the delusional mood (Wahnstimmung) that precedes the development of delirium is a sort of gateway to an impending psychotic illness, involving delusional awareness or mood (atmosphere). In psychosis, splitting is the main issue and this influence is seen as an evil, foreign, apocalyptic and unknown side no longer recognised as belonging to the self even in a physical sense. In such a situation, it is felt that the only way to survive is by suppressing one's double as a defense against disorganisation of the self.

Syndrome of subjective doubles as a rare presentation of a first-episode psychosis

In this paper, we report the case of a man in his 30s with a first-episode psychosis, characterised by a subtype of delusional misidentification syndrome in which the delusion of doubles is exclusively of the patient's own self. This subdivision can be termed 'syndrome of doubles of the self' or 'syndrome of subjective doubles'. Additionally, an examination of the patient's mental state showed paranoid delusions. After being evaluated in the emergency department, the patient was hospitalised, and medicated with antipsychotic drugs. One week later, he was discharged with total remission of psychotic symptoms. This is a rare and curious presentation of a psychotic episode, with very few similar cases described to date.

Coexistence of Different Delusional Misidentification Syndromes in Clinical Practice: A Case Series

OBJECTIVE

The objective of this study is to analyse the coexistence of several delusional misidentification syndromes in a clinical sample.

METHODS

Over one year, a sample of six patients presenting two or more types of delusional misidentification syndromes was selected. All these patients were admitted to the psychiatric inpatient unit of a Spanish hospital.

RESULTS

Despite the different diagnoses, the patients included presented different types of delusional misidentification syndromes, both hyperidentification and hypoidentification. Antipsychotic treatment was not very effective against these delusional misidentification syndromes CONCLUSIONS: The coexistence of several delusional misidentification syndromes indicates that the aetiopathogenesis of the different types is similar. It is a field with important clinical implications, due to the poor response to treatment, as well as the possible medico-legal implications.

Incidence and lesions causative of delusional misidentification syndrome after stroke

OBJECTIVE

To better elucidate the symptomatology and pathophysiological mechanisms underlying delusional misidentification syndrome (DMS), we investigated the incidence rate and symptomatic features of DMS following stroke and relationships among DMS, other neuropsychological symptoms, and lesion locations.

METHODS

The present study included 874 consecutive patients (371 women; mean age ± standard deviation = 72.2 ± 11.7 years) who were admitted to the rehabilitation wards at two hospitals within 2 months of their first stroke. We examined the clinical features and lesion sites of patients with DMS and compared them with those of a control group of patients with hemi-spatial neglect without DMS using voxel-based lesion-symptom mapping (VLSM).

RESULTS

Among the 874 patients who experienced a stroke, we observed 10 cases of Fregoli syndrome. No other DMS subtypes were observed; however, eight patients exhibited somatoparaphrenia (five of them also had Fregoli syndrome) and one also exhibited reduplicative paramnesia. Right hemispheric lesions were found in all 10 cases. VLSM revealed statistically significant overlapping lesion sites specifically related to Fregoli syndrome when compared with the control group. The sites included the insula, inferior frontal lobe, anterior temporal lobe, and subcortical limbic system in the right hemisphere (i.e., areas connected by the uncinate fasciculus).

CONCLUSION

The DMS incidence was 1.1% among patients after stroke. All patients had Fregoli syndrome and half had somatoparaphrenia, suggesting that the two syndromes share an underlying pathology. Lesions found with Fregoli syndrome were concentrated around the right uncinate fasciculus; this has not been reported in previous research.

Hallucinations, Delusions and Impulse Control Disorders in Parkinson Disease

Psychotic and compulsive symptoms in Parkinson disease are highly prevalent and associated with poor outcomes and greater caregiver burden. When acute, delirium should be ruled out or treated accordingly. When chronic, comorbid systemic illnesses, dementia, and psychiatric disorders should be considered. Reduction and discontinuation of anticholinergics, amantadine, dopamine agonists, and levodopa as tolerated, as well as adjunctive clozapine or quetiapine are frequently effective to manage Parkinson disease psychosis. Pimavanserin appears effective but is not widely available, and more experience is needed. Dopamine agonist discontinuation is usually successful for impulse control disorders, but requires frequent monitoring, documentation, and caregiver involvement.

The role of the IPL in person identification

We investigate the brain activations when identifying a newly encountered individual as being the same as a person previously perceived, a fundamental but seldom acknowledged process. In an identity condition, two faces had to be identified as the same person in contrast to a control condition, in which two faces had to be recognised as belonging to similar looking twins. Our results demonstrate an increase of neural activation in frontal as well as in parietal areas including the left inferior parietal lobe and the precuneus during identification. We introduce mental files theory to model this process as a linking of co-referential files and identify important connections to other domains in neurological and cognitive science (e.g., delusional misidentification syndromes, theory of mind).

Cognitive neuropsychiatric analysis of an additional large Capgras delusion case series

INTRODUCTION

Although important to cognitive neuropsychiatry and theories of delusions, Capgras delusion has largely been reported in single case studies. Bell et al. [2017. Uncovering Capgras delusion using a large scale medical records database. British Journal of Psychiatry Open, 3(4), 179-185] previously deployed computational and clinical case identification on a large-scale medical records database to report a case series of 84 individuals with Capgras delusion. We replicated this approach on a new database from a different mental health service provider while additionally examining instances of violence, given previous claims that Capgras is a forensic risk.

METHODS

We identified 34 additional cases of Capgras. Delusion phenomenology, clinical characteristics, and presence of lesions detected by neuroimaging were extracted.

RESULTS

Although most cases involved misidentification of family members or partners, a notable minority (20.6%) included the misidentification of others. Capgras typically did not present as a monothematic delusion. Few cases had identifiable lesions with no evidence of right-hemisphere bias. There was no evidence of physical violence associated with Capgras.

CONCLUSIONS

Findings closely replicate Bell et al. (2017). The majority of Capgras delusion phenomenology conforms to the "dual route" model although a significant minority of cases cannot be explained by this framework.

Psicopatologia em O duplo de Dostoiévski

O duplo aborda o tema da duplicidade do eu. Traz na narrativa descrições psicopatológicas da síndrome de duplos subjetivos e da esquizofrenia numa época em que essas condições ainda não tinham sido descritas. Este artigo situa a obra literária na história da psiquiatria, ressaltando o pioneirismo de Fiodor Dostoiévski, sua forma de narrar o tema e como conseguiu tratar o tema de forma clínica.

Uncovering Capgras delusion using a large-scale medical records database

BACKGROUND

Capgras delusion is scientifically important but most commonly reported as single case studies. Studies analysing large clinical records databases focus on common disorders but none have investigated rare syndromes.

AIMS

Identify cases of Capgras delusion and associated psychopathology, demographics, cognitive function and neuropathology in light of existing models.

METHOD

Combined computational data extraction and qualitative classification using 250 000 case records from South London and Maudsley Clinical Record Interactive Search (CRIS) database.

RESULTS

We identified 84 individuals and extracted diagnosis-matched comparison groups. Capgras was not 'monothematic' in the majority of cases. Most cases involved misidentified family members or close partners but others were misidentified in 25% of cases, contrary to dual-route face recognition models. Neuroimaging provided no evidence for predominantly right hemisphere damage. Individuals were ethnically diverse with a range of psychosis spectrum diagnoses.

CONCLUSIONS

Capgras is more diverse than current models assume. Identification of rare syndromes complements existing 'big data' approaches in psychiatry.

DECLARATION OF INTERESTS

V.B. is supported by a Wellcome Trust Seed Award in Science (200589/Z/16/Z) and the UCLH NIHR Biomedical Research Centre. S.W. is supported by a Wellcome Trust Strategic Award (WT098455MA). Q.D. has received a grant from King's Health Partners.

COPYRIGHT AND USAGE

© The Royal College of Psychiatrists 2017. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) license.

A Case of Reduplicative Paramnesia for Home

We present the case of a high-functioning 88-year-old woman who suddenly developed the persistent and disturbing belief that her home of 40 years was not genuine, but rather an accurate replica. Her episode was probably caused by a small stroke that left her with this single extremely specific deficit. We describe the patient in detail and link to a video interview of her 3 months after the onset of the delusion, eloquently describing her experience. We summarize some of the many reports and discussions of our patient's delusion, reduplicative paramnesia, as well as other delusional misidentification syndromes.

Psychosis

PURPOSE OF REVIEW

Psychosis is a common and functionally disruptive symptom of many psychiatric, neurodevelopmental, neurologic, and medical conditions and an important target of evaluation and treatment in neurologic and psychiatric practice. The purpose of this review is to define psychosis, communicate recent changes to the classification of and criteria for primary psychotic disorders described in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), and summarize current evidence-based approaches to the evaluation and management of primary and secondary psychoses.

RECENT FINDINGS

The DSM-5 classification of and criteria for primary psychotic disorders emphasize that these conditions occur along a spectrum, with schizoid (personality) disorder and schizophrenia defining its mild and severe ends, respectively. Psychosis is also identified as only one of several dimensions of neuropsychiatric disturbance in these disorders, with others encompassing abnormal psychomotor behaviors, negative symptoms, cognitive impairments, and emotional disturbances. This dimensional approach regards hallucinations and delusions as arising from neural systems subserving perception and information processing, thereby aligning the neurobiological framework used to describe and study such symptoms in primary psychotic disorders with those used to study psychosis associated with other neurologic conditions.

SUMMARY

This article provides practicing neurologists with updates on current approaches to the diagnosis, evaluation, and treatment of primary and secondary psychoses.

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.

Delusional misidentification syndromes and dementia: a border zone between neurology and psychiatry

The delusional misidentification syndromes (DMSs) are psychopathologic phenomena in which a patient consistently misidentifies persons, places, objects, or events. Although often described in relation to psychotic states including schzofrenia, it is, nevertheless, widely considered that these syndromes have an anatomical basis because of their frequent association with organic brain disease; studies have pointed to the presence of identifiable lesions, especially in the right frontal lobe and adjacent regions, in a considerable proportion of patients. The purpose of this article is to examine the phenomenon in people with dementia. We searched the electronic databases for original research and review articles on DMS in patients with dementia using the search terms "Delusional Misidentification Syndrome, Capgras syndrome, Fregoli syndrome, reduplicative paramnesia, and dementia." The DMSs are a frequent problem in dementia. The violence and dangerousness in patients with dementia having these syndromes are well documented, and forensic aspects are highlighted. Pathogenetic viewpoint and management are considered.

Delusional misidentification syndromes in obsessive-compulsive disorder

Delusional misidentification syndromes (DMS) have been rarely reported in patients with conditions other than schizophrenia-related disorders, diffuse brain disease (dementia) and focal neurological illness. In this report, we describe DMS (i.e. Capgras and Fregoli syndromes) in two patients with severe and treatment resistant obsessive-compulsive disorder (OCD), one with paranoid personality disorder (PPD) and the other with a pervasive developmental disorder (PDD) not otherwise specified. While our findings highlight an interesting phenomenon (the occurrence of DMS in OCD), it is presently unclear whether this association is rare or underreported. Misidentification syndromes might be the ultimate result of a combination of obsessive fears and preexisting cognitive bias/deficits, such as mistrustfulness (in PPD) or poor theory of mind (in PDD).

The human frontal lobes and frontal network systems: an evolutionary, clinical, and treatment perspective

Frontal lobe syndromes, better termed as frontal network systems, are relatively unique in that they may manifest from almost any brain region, due to their widespread connectivity. The understandings of the manifold expressions seen clinically are helped by considering evolutionary origins, the contribution of the state-dependent ascending monoaminergic neurotransmitter systems, and cerebral connectivity. Hence, the so-called networktopathies may be a better term for the syndromes encountered clinically. An increasing array of metric tests are becoming available that complement that long standing history of qualitative bedside assessments pioneered by Alexander Luria, for example. An understanding of the vast panoply of frontal systems' syndromes has been pivotal in understanding and diagnosing the most common dementia syndrome under the age of 60, for example, frontotemporal lobe degeneration. New treatment options are also progressively becoming available, with recent evidence of dopaminergic augmentation, for example, being helpful in traumatic brain injury. The latter include not only psychopharmacological options but also device-based therapies including mirror visual feedback therapy.

Capgras Syndrome associated with the use of psychoactive substances

INTRODUCTION

Capgras syndrome has originally been described as psychiatric syndrome. However, in the last few years reports of patients with this syndrome has significantly increased in patients with neurological, metabolic, and infectious diseases and those who consume alcohol. Different hypotheses have been proposed to explain the neurobiology of this very unusual symptom, such as changes in the dopamine circuit and specific dysfunctions in facial processing.

CASE

In this work we present a new case of Capgras syndrome, associated with an acute cocaine overdose, which was transient and reversible.

DISCUSSION

The neurobiological bases of this syndrome are analysed, along with their relationship with the changes induced by cocaine use. Thus, Capgras syndrome could be the expression of functional changes at frontal-temporal level, and the paralimbic region secondary to the consumption of psychoactive substances such as cocaine.

Fregoli syndrome: an underrecognized risk factor for aggression in treatment settings

Fregoli syndrome (FS) is commonly associated with verbal threats and aggressive behavior. We present a case of Fregoli syndrome leading to an assault. We discuss the possible underdiagnosis of FS, associated risk for aggression, and strategies to reduce that risk.

Olfactory Delusional Syndrome and Intracranial Meningioma

We report the case of a 37-year-old female in which the removal of a suprasellar neoplasm was accompanied by the disappearance of a longstanding olfactory delusion syndrome. In primary care the patient condition was exclusively thought to be psychic in origin, neglecting the possible, not infrequent, organic contribution. The delayed diagnosis produced neurological impairment, only partially recovered after surgical therapy. This case might help to improve the patient management via multi-specialist cooperation and to broaden the knowledge about somatic mechanisms of psychic disturbances, are not often taken into account.