Monothematic Delusions Research Articles

Making Sense of an Endorsement Model of Thought‐Insertion

AbstractExperiences of thought‐insertion are a first‐rank, diagnostically central symptom of schizophrenia. Schizophrenic patients who undergo such delusional mental states report being first‐personally aware of an occurrent conscious thought which is not theirs, but which belongs to an external cognitive agent. Patients seem to be right about what they are thinking but mistaken about who is doing the thinking. It is notoriously difficult to make sense of such delusions. One general approach to explaining the etiology of monothematic delusions has come to be known as the endorsement model. This model claims that the patient holds her delusional belief because she simply trusts her bizarre experience and takes it at face value. The content of the bizarre experience thus plays a central role in the etiology of delusions. Despite being widely discussed with respect to delusions like Capgras and Cotard, an endorsement model of thought‐insertion has not yet been formulated. This article seeks to fill this void by fleshing out and defending the endorsement approach to delusions of inserted thoughts. It aims to show that such an approach can be defended against objections that have been raised in the literature. In particular, it will be argued that there is nothing wrong with the idea of being first‐personally aware of a thought which is presented in consciousness as being someone else's. The upshot is that with respect to delusions of thought‐insertion, the endorsement model turns out to be a viable account of why patients come to believe that someone else is inserting thoughts into their minds.

When Words Speak Louder than Actions: Delusion, Belief, and the Power of Assertion

People suffering from severe monothematic delusions, such as Capgras, Fregoli, or Cotard patients, regularly assert extraordinary and unlikely things. For example, some say that their loved ones have been replaced by impostors. A popular view in philosophy and cognitive science is that such monothematic delusions aren't beliefs because they don't guide behaviour and affect in the way that beliefs do. Or, if they are beliefs, they are somehow anomalous, atypical, or marginal beliefs. We present evidence from five studies that folk psychology unambiguously views monothematic delusions as stereotypical beliefs. This calls into question widespread assumptions in the professional literature about belief's stereotypical functional profile. We also show that folk psychology views delusional patients as holding contradictory beliefs. And we show that frequent assertion is a powerful cue to belief ascription, more powerful than even a robust and consistent track record of non-verbal behaviour.

Clinical Lycanthropy: Delusional Misidentification of the “Self”

Clinical Lycanthropy: Delusional Misidentification of the “Self”

La perte de contingence : un concept phénoménologique renseignant les modèles cognitifs du délire de type paranoïaque

ObjectivesWhen researching delusions, cognitive sciences have developed certain models involving philosophy, psychology and neuroscience but these mainly focus on a monothematic delusion (such as the Capgras syndrome) and schizophrenia. Paranoia is a princeps clinical entity in the psychopathological tradition of psychoses. Persecutory delusion has recently been the subject of specific studies focusing on attention and cognitive models, whether general or specific (Bentall, Freeman), and isolating a number of factors. We propose to analyze the pertinence of these models in order to test their fruitfulness. We have attempted to put data from cognitive sciences and clinical knowledge in order. MethodA review underscores the cognitive approach to persecutory delusion. On the one hand, general or specific models are available, on the other, several cognitive mechanisms are thought to be impaired. Moreover, in accordance with an interdisciplinary view, we propose to bring the philosophical concept of contingency into the cognitive psychology of paranoia. According to Minkowski, loss of contingency is hypothesized to be the fundamental disorder concerning “being in the world” of paranoia. ResultsThree main models attempt to explain delusion: firstly, top-down account that considers delusion as a high order defect; secondly, bottom-up account where the first problem comes from experience; thirdly, a mixed model which associates low and high order levels. This splitting between percept and intellect is not very interesting for paranoia. Elsewhere, specific models place paranoia as a way of defense against depression (Bentall) and paranoia as directly reflecting anxiety (Freeman). According to these points of view, paranoia is not a specific disorder. On the contrary, loss of contingency as the primary disturbance enables us to specify paranoia. With this in mind, attribution's style is strained, the theory of mind is hypertrophied and social and emotional perception disorders are understood and, likewise, reasoning biases (jumping-to-conclusion, need to closure) highlight a kind of irrationality. DiscussionTraditionally, research in cognitive sciences is interdisciplinary. By integrating a concept derived from phenomenology and clinical tradition, we gain in fruitfulness. In fact, specific models that are actually available rely on ideas stemming from affective psychopathology: depression and anxiety. If you grasp paranoia as a specific phenomenon according to the history of psychiatry, you can propose a model more fitting to clinical reality. Nevertheless, loss of contingency does not fit all experimental data. We notice that some data are partially conflicting and patch worked. A challenge remains to define paranoia well: the actual definition, according to the DSM IV-TR, is too restricted. Indeed, paranoia is not only persecutory delusion. Moreover, interpretation and systematization are critical concepts when targeting paranoia outside of the field of schizophrenia. ConclusionLoss of contingency is therefore a heuristic hypothesis which best explains most data and provides a new perspective to orient future cognitive experimental research, especially in the field of virtual reality. The clinical features of paranoia are highly suitable for cognitive studies in order to improve accounts.

Failing to self-ascribe thought and motion: Towards a three-factor account of passivity symptoms in schizophrenia

There has recently been emphasis put on providing two-factor accounts of monothematic delusions. Such accounts would explain (1) whether a delusional hypothesis (e.g. someone else is inserting thoughts into my mind) can be understood as a prima facie reasonable response to an experience and (2) why such a delusional hypothesis is believed and maintained given its implausibility and evidence against it. I argue that if we are to avoid obfuscating the cognitive mechanisms involved in monothematic delusion formation we should split the first factor (1 above) into two factors: how abnormal experience can give rise to a delusional ‘proto-hypothesis’ and how a ‘proto-hypothesis’ in consort with normal experiences and background information, can be developed into a delusional hypothesis. In particular I will argue that a schizophrenic is faced with the unusual requirement of having to identify an introspectively accessible thought as one's own, and that this requirement of identification is the central experiential abnormality of thought insertion, auditory verbal hallucination, and alien control (i.e. passivity symptoms). Additionally, I will consider non-experiential factors which are required for the formation of a delusional hypothesis.

On the Distinction between Monothematic and Polythematic Delusions

Some delusional patients exhibit only a single delusional belief (or several delusional beliefs concerning a single theme): this is monothematic delusion. It contrasts with polythematic delusion, where the patient exhibits a variety of delusions concerning a variety of different themes. The neuropsychological bases of various monothematic delusions are rather well understood, and there is a well‐worked‐out general neuropsychological theory of monothematic delusion, the two‐factor theory. Whether polythematic delusion might be explained in a similar way is an open question: I sketch some possible ways in which a comparable two‐factor account might be developed for polythematic (‘psychiatric’) delusional conditions such as delusions of reference.

When Words Speak Louder than Actions: Delusion, Belief, and the Power of Assertion

People suffering from severe mono-thematic delusions, such as Capgras, Fregoli or Cotard patients, regularly assert extraordinary and unlikely things. For example, some say that their loved ones have been replaced by impostors. A popular view in philosophy and cognitive science is that such mono-thematic delusions aren’t beliefs because they don’t guide behavior and affect in the way that beliefs do. Or, if they are beliefs, they are somehow anomalous, atypical, or marginal beliefs. We present evidence from five studies that folk psychology unambiguously views mono-thematic delusions as stereotypical beliefs. This calls into question widespread assumptions in the professional literature about belief’s stereotypical functional profile. We also show that folk psychology views delusional patients as holding contradictory beliefs. And we also show that frequent assertion is a powerful cue to belief-ascription, more powerful than even a robust and consistent track record of non-verbal behavior.

996 – Capgras syndrome in a three-decades non-treated schizophrenia: a case report

Introduction Capgras syndrome is a misidentification syndrome typically characterized by the delusional belief that a close relative has been replaced by an impostor. This monothematic delusion can be found in numerous disorders such as paranoid schizophrenia, schizoaffective disorder, affective disorders, Alzheimer's disease, Lewy body dementia, head trauma, epilepsy, cerebrovascular disease and dementia, pituitary tumor, multiple myeloma, multiple sclerosis, viral encephalitis, frontal lobe pathology and AIDS. We present a case of a patient that presents Capgras Syndrome at the first psychiatric evaluation in the context of three-decades untreated paranoid schizophrenia. Case report A 56-year-old woman was brought to the psychiatric department for evaluation for aggressive behavior directed to relatives. She has a history of auditory hallucinations, experiences of self-reference and paranoid delusions with more than 30 years of evolution. More recently, she started becoming aggressive with relatives, saying her real family members had been taken by strangers to an unknown hospital. She also said that her ID photo had been replaced by another person's photo. After detailed psychiatric evaluation, blood analysis and imaging study, the diagnosis of Paranoid Schizophrenia was established. She was treated with olanzapine 20mg/day with behavioral improvement. Conclusions Although Capgras Syndrome is not a psychiatric diagnosis but a feature of several different conditions, psychiatrists should be aware of this syndrome as it can signalize underlying psychiatric disorders and is usually associated with violent behaviors that should be managed.

Delusional Misidentification Syndrome (DMS) - An unidentified entity of DSM

Delusional misidentification syndromes (DMS), which includes the Capgras, Fregoli, Inter metamorphosis and Syndrome of Subjective doubles gain curiosity due to the bizarreness in their symptomatology. However they are diagnosed as some form of Schizophrenia and related psychosis and treated accordingly. An issue that remains unresolved is whether DMS (either in its pure form or as embedded symptoms of other diagnoses) can be accommodated in the present Diagnostic and Statistical Manual of Mental Disorders, (DSM-IV TR). As we await the DSM – V, it is still not clear as where do we diagnose patients with monothematic bizarre delusions due to lack of proper guidelines in DSM IV TR. Here we present two cases with Capgras Delusions and express our concern regarding the short comings of current Diagnostic system

Bimanual coupling paradigm as an effective tool to investigate productive behaviors in motor and body awareness impairments

When humans move simultaneously both hands strong coupling effects arise and neither of the two hands is able to perform independent actions. It has been suggested that such motor constraints are tightly linked to action representation rather than to movement execution. Hence, bimanual tasks can represent an ideal experimental tool to investigate internal motor representations in those neurological conditions in which the movement of one hand is impaired. Indeed, any effect on the “moving” (healthy) hand would be caused by the constraints imposed by the ongoing motor program of the ‘impaired’ hand. Here, we review recent studies that successfully utilized the above-mentioned paradigms to investigate some types of productive motor behaviors in stroke patients. Specifically, bimanual tasks have been employed in left hemiplegic patients who report illusory movements of their contralesional limbs (anosognosia for hemiplegia). They have also been administered to patients affected by a specific monothematic delusion of body ownership, namely the belief that another person’s arm and his/her voluntary action belong to them. In summary, the reviewed studies show that bimanual tasks are a simple and valuable experimental method apt to reveal information about the motor programs of a paralyzed limb. Therefore, it can be used to objectively examine the cognitive processes underpinning motor programming in patients with different delusions of motor behavior. Additionally, it also sheds light on the mechanisms subserving bimanual coordination in the intact brain suggesting that action representation might be sufficient to produce these effects.

Pain and Body Awareness: Evidence from Brain-Damaged Patients with Delusional Body Ownership

A crucial aspect for the cognitive neuroscience of pain is the interplay between pain perception and body awareness. Here we report a novel neuropsychological condition in which right brain-damaged patients displayed a selective monothematic delusion of body ownership. Specifically, when both their own and the co-experimenter’s left arms were present, these patients claimed that the latter belonged to them. We reasoned that this was an ideal condition to examine whether pain perception can be “referred” to an alien arm subjectively experienced as one’s own. Seventeen patients (11 with, 6 without the delusion), and 10 healthy controls were administered a nociceptive stimulation protocol to assess pain perception. In the OWN condition, participants placed their arms on a table in front of them. In the ALIEN condition, the co-experimenter’s left (or right) arm was placed alongside the participants’ left (or right) arm, respectively. In the OWN condition, left (or right) participants’ hand dorsum were stimulated. In the ALIEN condition, left (or right) co-experimenter’s hand dorsum was stimulated. Participants had to rate the perceived pain on a 0–5 Likert scale (0 = no pain, 5 = maximal imaginable pain). Results showed that healthy controls and patients without delusion gave scores higher than zero only when their own hands were stimulated. On the contrary, patients with delusion gave scores higher than zero both when their own hands (left or right) were stimulated and when the co-experimenter’s left hand was stimulated. Our results show that in pathological conditions, a body part of another person can become so deeply embedded in one’s own somatosensory representation to effect the subjective feeling of pain. More in general, our findings are in line with a growing number of evidence emphasizing the role of the special and unique perceptual status of body ownership in giving rise to the phenomenological experience of pain.

Vorhersagefehler und Gehirnverletzungen. Zwei-Faktoren-Theorien über Wahnvorstellungen

Abstract This paper explores the two-factor theoretical model currently widely used to provide an explanatory analysis of the delusions that regularly accompany neurological disease or damage. The model hypothesizes a combination of an experiential factor – a strange or untoward experience – and a cognitive factor, such as an impairment of reasoning. The two-factor model has been devised for monothematic delusions that are usually manifested in a single, implausible idea. These have to be distinguished from the more elaborated, polythematic delusions that are found in psychiatry. Psychiatric delusions exceed neurological ones in frequency and, often, semantic complexity. This text offers a preliminary clarification of underlying assumptions about the breadth, terminology and presuppositions of two-factor theorizing, exploring its potential application to psychiatric delusions.

Síndrome de Ekbom en consumidor de metilfenidato intravenoso

Ekbom syndrome is a mental disorder in which the patient has the monothematic delusion of being infected by parasites. It is an uncommon condition that was initially studied by dermatologists. The exactly etiology is unknown to date, though several causes have been proposed, including metabolic diseases (among other physical causes), psychiatric disorders, drugs, etc. Research has now found a relationship between drug abuse and psychotic symptoms, which appear to be due to altered levels of dopamine at the receptor level. In this article we review the clinical features of the condition and present the case report of an intravenous methylphenidate abuser who developed a delusion of parasitosis.

P-227 - At the basis of the identity. The delusional misidentification syndromes

Background The Delusional Misidentification Syndromes (MDS) are a group of monothematic delusions where the process of misidentification affects selectively people, objects and places. Their common denominator is a disturbance of the identification of the object, final stage of the mechanism of perception. Method From the context of DMS, and specifically of the personal identification delusions (PID) whose main characteristics are recalled, the objective is here to study the basic elements of the concept of identity. Results Two main basis for self-recognition are detailed: the body and the subject's name. The body is the privileged place where the identity of the subject appears in its singularity. Merleau-Ponty regarded it as the stable structure of existence, “place of appropriation of the world”, allowing the existence of objects. It appears in two ways as a support of the identity, while linking it on one hand to the subject about who feels it like its own, and on the other hand to others who recognize it as the one of the subject. The name acts as a “classifier of lineage” according to Levi-Strauss, by locating the subject and its family from the rest of the social group. It enrolls the individual in a temporality punctuated by the difference between generations. Conclusion The feeling of identity appears as an inner certitude which impregnates all experience. Mental illness can question it, like delusions centered on identity by referring to the fundamental question of the origin.

Mirrored-self misidentification in the hypnosis laboratory: Recreating the delusion from its component factors

Introduction. Mirrored-self misidentification is the delusional belief that one's reflection in the mirror is a stranger. According to Langdon and Coltheart's (2000) “two-factor” theory of monothematic delusions, the delusion can arise from deficits in face processing (Factor 1) and belief evaluation (Factor 2). This study gave participants separate hypnotic suggestions for these two factors to create a hypnotic analogue of the delusion. Method. Forty-six high hypnotisable participants received a hypnotic suggestion for either Factor 1 alone or for Factors 1 and 2, either with hypnosis (hypnosis condition) or without (wake condition). Participants were asked to look into a mirror and to describe what they saw. Participants who reported seeing a stranger in the mirror also received a series of challenges. Results. Overall, 70% of participants in the hypnosis condition passed the delusion; only 22% of participants in the wake condition passed. Importantly, in hypnosis, the Factor 1 alone suggestion was just as effective in creating the delusion as the combined Factor 1 and Factor 2 suggestion. Conclusion. These results suggest that hypnotic suggestion can recreate the mirrored-self misidentification delusion from its component factors. Notably, the hypnotic context, itself known to disrupt belief evaluation, can act as Factor 2.

Delusional Belief

Delusional beliefs are seen in association with a number of neuropathological conditions, including schizophrenia, dementia, and traumatic brain injury. A key distinction exists between polythematic delusion (here the patient exhibits delusional beliefs about a variety of topics that are unrelated to each other) and monothematic delusion (here the patient exhibits just a single delusional belief or else a small set of delusional beliefs that are all related to a single theme). A great deal of recent research has focused on identifying and investigating various different forms of monothematic delusion. We discuss a general theoretical approach to the understanding of monothematic delusions--a two-factor approach according to which understanding the nature and genesis of any kind of monothematic delusion involves seeking answers to two questions. The first question is, what brought the delusional idea to mind in the first place? The second question is, why is this idea accepted as true and adopted as a belief when the belief is typically bizarre and when so much evidence against its truth is available to the patient? We discuss in detail six different kinds of monothematic delusion, showing for each how neuropsychological considerations allow a first factor (responsible for the content of the belief) and a second factor (responsible for the failure to reject the belief) to be plausibly identified. Five difficulties confronting this two-factor account of monothematic delusion are then identified, and attempts are made to address each one.

Les cénesthopathies : un trouble des émotions d’arrière plan. Regards croisés des sciences cognitives et de la phénoménologie

Cenesthesia and cenesthopathy have played a fundamental role in 19th and early 20th century French and German psychiatry. Cenesthesia refers to the internal, global, implicit and affective perception of one's own body. The concept of cenesthopathy was coined by Dupre and Camus in 1907 to describe a clinical entity characterized by abnormal and strange bodily sensations. In this review, we examine the history of these concepts and the influence they have had on clinical, nosographical and phenomenological psychiatry and on cognitive neuropsychiatry. We performed a narrative review of the published research literature. Classical French and German psychiatrists have written extensively on cenesthesia and cenesthopathy although these notions are no longer in the mainstream of contemporary psychiatry. However, they are still present in contemporary psychiatric nosography in the form of some controversial clinical entities clearly related to cenesthesia such as cenesthetic schizophrenia, hypochondriacal monothematic delusions, or the Capgras and the Cotard syndromes. These clinical entities are all associated with a state of depersonalization. We point out the similarities between Ey's description of the depersonalization syndrome, especially in psychosis, and the characteristics of cenesthesia. Philosophers like Sartre or Merleau-Ponty have developed the concept of cenesthesia, and in particular have added new concepts like "body schema". Similarly, phenomenological psychiatrists like Minkowski or Tellenbach have attempted to describe psychiatric disorders associated with cenesthesia and have also proposed new concepts (i.e. atmospheric sense) in order to understand them better. More recently, cognitive neuropsychiatry has tried to discover the mechanisms, which cause or contribute to the genesis of delusions. The majority of delusion theories developed in cognitive neuropsychiatry consider that the explanation of monothematic delusions involves one or two explanatory stages. The first stage corresponds to an abnormal experience (the experiential stage) while the second is related to abnormal reasoning (the inferential stage). This theoretical first stage has been considered to be the result of a highly unusual or bizarre perceptual experience. According to the authors, this experience refers to a phenomenon of depersonalization, a loss of cenesthesia, or a loss of a feeling of familiarity. For example, the neurocognitive models of the Capgras and Cotard syndromes have in common the belief that they are both based on various kinds of unusual experiences. These unusual experiences are thought to include affective or emotional experiences. Capgras' syndrome is possibly triggered by an abnormal affective experience in response to the sight of closed-person's face. Similarly, the Cotard syndrome may result from a general flattening of affective responses to external stimuli. The inferential stage can also differentiate between the two syndromes. Some empirical validation has already been obtained in Capgras' syndrome but not yet in Cotard's syndrome. This review illustrates that the historical descriptions of cenesthesia and cenesthopathy remain relevant in contemporary neurocognitive models and more generally suggests that the comprehension of quite complex phenomena like delusion requires a multidisciplinary approach.

The cognitive neuropsychiatry of delusional belief.

According to the 'two-factor' cognitive-neuropsychiatric approach to delusional belief, two factors, in combination, explain the generation and maintenance of monothematic delusions. The first factor varies from delusion to delusion and explains why a patient generates a particular implausible thought in the first place. The second factor explains why a patient fails to reject the implausible thought as belief. This two-factor approach began with a 'two-deficit' account of bizarre monothematic delusions, according to which bizarre delusions are generated when a (first-factor) deficit of basic sensory/affective processing fundamentally distorts perceived reality. Deficits of this type are discussed and contrasted with motivated attentional biases in more mundane delusions. To better specify the second factor, I contrast 'explanationist' and 'endorsement' approaches to the role of aberrant experience in delusion formation and propose a 'received-reflective' spectrum. At one pole of this spectrum are purely received delusions, which arise fully formed and fully (mis)believed in consciousness as the (mis)perceived reality. At the other pole are purely reflective delusions, which arise after reflection upon a vague and disquieting experience, and for which the crystallization of delusional conviction is more gradual. Most delusions lie in between, a mix of received 'delusional seed' and reflective elaboration. Underpinning all monothematic delusions, wherever they might lie on this spectrum may be a form of 'doxastic inhibitory failure'-a difficulty with inhibiting a belief to reason about it as if it might not be true. I conclude by considering how this account might apply to polythematic delusions. WIREs Cogni Sci 2011 2 449-460 DOI: 10.1002/wcs.121 For further resources related to this article, please visit the WIREs website.

Schizophrenia and Monothematic Delusions

Numerous delusions have been studied which are highly specific and which can present in isolation in people whose beliefs are otherwise entirely unremarkable - "monothematic delusions" such as Capgras or Cotard delusions. We review such delusions and summarize our 2-factor theory of delusional belief which seeks to explain what causes these delusional beliefs to arise initially and what prevents them being rejected after they have arisen. Although these delusions can occur in the absence of other symptoms, they can also occur in the context of schizophrenia, when they are likely to be accompanied by other delusions and hallucinations. We propose that the 2-factor account of particular delusions like Capgras and Cotard still applies even when these delusions occur in the context of schizophrenia rather than occurring in isolation.

Unusual Experiences, Reality Testing and Delusions of Alien Control

: Some monothematic types of delusions may arise because subjects have unusual experiences. The role of this experiential component in the pathogenesis of delusion is still not understood. Focussing on delusions of alien control, we outline a model for reality testing competence on unusual experiences. We propose that nascent delusions arise when there are local failures of reality testing performance, and that monothematic delusions arise as normal responses to these. In the course of this we address questions concerning the tenacity with which delusions are maintained, their often bizarre content, the patients’ inability to dismiss them, and their often circumscribed character.