Monothematic Delusions Research Articles

Monothematic delusions are misfunctioning beliefs

Monothematic delusions are bizarre beliefs which are often accompanied by highly anomalous experiences. For philosophers and psychologists attracted to the exploration of mental phenomena in an evolutionary framework, these beliefs represent—notwithstanding their rarity—a puzzle. A natural idea concerning the biology of belief is that our beliefs, in concert with relevant desires, help us to navigate our environments, and so, in broad terms, an evolutionary story of human belief formation will likely insist on a function of truth (true beliefs tend to lead to successful action). Monothematic delusions are systematically false and often harmful to the proper functioning of the agent and the navigation of their environment. So what are we to say? A compelling thought is that delusions are malfunctioning beliefs. Compelling though it may be, I argue against this view on the grounds that it does not pay due attention to the circumstances in which monothematic delusions are formed, and fails to establish doxastic malfunction. I argue instead that monothematic delusions are misfunctioning beliefs, that is, the result of mechanisms of belief formation operating in historically abnormal conditions. Monothematic delusions may take their place alongside a host of other strange beliefs formed in difficult epistemic conditions, but for which no underlying doxastic malfunction is in play.

Delusional parasitosis (Ekbom Syndrome): A case report

Background: Ekbom syndrome or Delusional Parasitosis (DP) is an infrequent psychotic illness, where the patient has a false but firm and strong belief that his body is infested with parasites, worms, insects, or other organisms. This is a monothematic delusion of hallucinatory origin that typically affects older women. The aim: To report two cases of DP. Case report: The first patient presented a generalized sensation of parasite infestation following ischemic stroke. In the second case, the delusions of parasitosis were concentrated in the head only. Conclusion: Delusional parasitosis (DP) or Ekbom syndrome is an infrequent psychotic illness. Collaboration between dermatologists and psychiatrists is important in managing this rare disease. Neurologists must be aware of DP in patients with stroke.

Capgras Syndrome with Non-Violent Behaviour Presenting in Postpartum Period: Case Study with Literature Review

Background: Capgras syndrome (CS) is one of the delusional misidentification syndromes (DMS) characterized by the belief by the patient that the close person, usually a close relative or family member is replaced by an imposter who looks physically the same. Since the first case of Capgras syndrome was described in 1923, the published literature is confined to a small number of case reports and a single case series. Capgras syndrome rarely occurs in postpartum period; there are few references in the literature to any of the delusions of misidentification occurring in a post partum period. Moreover, some authors described Capgras syndrome as frequently involving hostility, violence and risk of neglect towards an object of delusional misidentification. Their reports based on single cases report or small case series that may be subject to significant reporting bias. This case outlined here on a female patient affected by Capgras syndrome in post partum period with brief review of the literature. Case presentation: A 32-year-old woman presented to the psychiatric clinic for a delusional belief that newborn had been replaced by another one. Capgras delusion was developed after caesarean section on her 12th postpartum day. The patient was healthy individual whose Capgras syndrome was not linked to any psychiatric or neurological states in the past. Anxiety and depressive symptoms followed progressively without postpartum psychosis. Though she has a fixed belief, which is that her baby was replaced by another one, she did not show any psychotic features or aggression behaviour. Conclusion: In this case report, Capgras syndrome is typically a monothematic delusion (delusion about the baby may have an altered identity or replaced by another one) and is not accompanied by other delusions. Also, it displays the course of anxiety and depression in the period of postpartum period that accompanied with Capgras syndrome. The patient has no postpartum psychosis, only a delusion about the baby replaced by another one. Though her ambivalent emotions toward the baby, the patient did not show any hostility, aggression behaviour or violence and denied thoughts of harming baby.

Philosophy's Role in Theorizing Psychopathology

Abstract: It is a mistake to think that any philosophical contribution to the study of psychopathology is otiose. I identify three non-exhaustive roles that philosophy can and does occupy in the study of mental disorder, which I call the agenda-setting role, the synthetic role, and the regulative role. The three roles are illustrated via consideration of the importance of Jaspers' notion of understanding and its application to specific examples of mental disorder, including delusions of reference, Capgras delusion and other monothematic delusions, and clinical depression. Together the three roles assign to philosophy of psychopathology the task of determining how to situate the varieties of mental disorder within the system of interpretive and evaluative concepts that partially make up the dynamic but indispensable manifest image.

Monothematic Delusions and the Limits of Rationality

Monothematic Delusions and the Limits of Rationality

Thanatotic Infestation: Ekbom’s Syndrome as an Exordium to Cotard’s Delusion

AbstractIntroductionEkbom’s delusion as a prelude to Cotard’s syndrome, has not heretofore been described.MethodsCase study: A 45-year-old woman with a past diagnosis of bipolar disorder with psychotic features was admitted, having been up all night conversing with spirits, proclaiming that she had made a deal with Satan. Convinced that her grandmother was possessed by the devil, she smashed her grandmother’s head with a two-by-four. Results: Mental Status Examination: self conversing with her eyes darting around the room. Poor hygiene. Behavior: guarded and withdrawn. Oriented x2. Speech: hyperverbal. Insight and judgment: poor. Mood: hostile, aggressive, and angry. Thought process disorganized, incongruent, and tangentiality. She was convinced she was infested with little black bugs crawling around her insides which had been placed there by the devil. After two days of olanzapine she reported the bugs were no longer present, but rather that she herself was dead and that her organs were decomposing, which persisted through the remainder of the hospitalization.DiscussionNeuroimaging abnormalities in Ekbom’s syndrome involve the striatum, basal ganglia (putamen and caudate nucleus), insular and cingulate cortices, cortex (prefrontal, right parietal, and temporal lobes), right lingual and orbitofrontal gyri, and thalamus. In Cotard’s syndrome, abnormalities have been identified in the striatum, frontal and temporal lobes, and right-sided and bilateral hemispheres. An overlap between the delusions exists in the striatum, inferior parietal, and temporal lobes. A single lesion in the nondominant inferior parietal lobe may cause both syndromes, due to its substantial interconnection with the temporo-limbic areas. Since the parietal lobe is also involved in somatosensory processing, peradventure distorted sensory perception with associated sensation of formication may have been the nidus for the delusional infestation as well as a nidus for the perception of thanatos habitus. Such misperception may have then been amplified into a delusion because of a hyperconnection between the parietal lobe and the limbic system. This may represent a variant of the two-factor hypothesis of delusions whereby a distorted sensory perception is then misrepresented in a delusion. Dysfunction of the right hemisphere, which normally acts to censor the left, allows the delusion to manifest. A single lesion of the inferior parietal lobule may be sufficient for both sensory distortions and loss of inhibition of delusional interpretation of distorted sensation by the frontal lobe, yclept the sensorialist hypothesis.ConclusionIn those with monothematic delusions, the search for transient fluctuation in delusional states may be revealing.FundingNo Funding

The clinical significance of anomalous experience in the explanation of monothematic delusions

Monothematic delusions involve a single theme, and often occur in the absence of a more general delusional belief system. They are cognitively atypical insofar as they are said to be held in the absence of evidence, are resistant to correction, and have bizarre contents. Empiricism about delusions has it that anomalous experience is causally implicated in their formation, whilst rationalism has it that delusions result from top down malfunctions from which anomalous experiences can follow. Within empiricism, two approaches to the nature of the abnormality/abnormalities involved have been touted by philosophers and psychologists. One-factor approaches have it that monothematic delusions are a normal response to anomalous experiences whilst two-factor approaches seek to identify a clinically abnormal pattern of reasoning in addition to anomalous experience to explain the resultant delusion. In this paper we defend a one-factor approach. We begin by making clear what we mean by atypical, abnormal, and factor. We then identify the phenomenon of interest (monothematic delusion) and overview one and two-factor empiricism about its formation. We critically evaluate the cases for various second factors, and find them all wanting. In light of this we turn to our one-factor account, identifying two ways in which ‘normal response’ may be understood, and how this bears on the discussion of one-factor theories up until this point. We then conjecture that what is at stake is a certain view about the epistemic responsibility of subjects with delusions, and the role of experience, in the context of familiar psychodynamic features. After responding to two objections, we conclude that the onus is on two-factor theorists to show that the one-factor account is inadequate. Until then, the one-factor account ought to be understood as the default position for explaining monothematic delusion formation and retention. We don’t rule out the possibility that, for particular subjects with delusions there may be a second factor at work causally implicated in their delusory beliefs but, until the case for the inadequacy of the single factor is made, the second factor is redundant and fails to pick out the minimum necessary for a monothematic delusion to be present.

Unimpaired abduction to alien abduction: Lessons on delusion formation

ABSTRACT An examination of alien abduction belief can inform how we ought to approach constructing explanations of monothematic delusion formation. I argue that the formation and maintenance of alien abduction beliefs can be explained by a one-factor account, and that this explanatory power generalizes to (other) cases of monothematic delusions. There are no differences between alien abduction beliefs and monothematic delusions which indicate the need for additional explanatory factors in cases of the latter. I make the additional point that whilst alien abduction beliefs can be readily explained using a one-factor framework, the two-factor framework requires adjustment to accommodate them. I conclude that theorists interested in delusion formation have much to learn from the case of alien abduction belief.

The anatomo-clinical picture of the pathological embodiment over someone else's body part after stroke

Recently, a monothematic delusion of body ownership due to brain damage (i.e., the embodiment of someone else's body part within the patient's sensorimotor system) has been extensively investigated. Here we aimed at defining in-depth the clinical features and the neural correlates of the delusion. Ninety-six stroke patients in a sub-acute or chronic phase of the illness were assessed with a full ad-hoc protocol to evaluate the embodiment of an alien arm under different conditions. A sub-group of seventy-five hemiplegic patients was also evaluated for the embodiment of the movements of the alien arm. Fifty-five patients were studied to identify the neural bases of the delusion by means of voxel-based lesion-symptom mapping approach. Our results show that, in forty percent of the whole sample, simply viewing the alien arm triggered the delusion, but only if it was a real human arm and that was seen from a 1st person perspective in an anatomically-correct position. In the hemiplegic sub-group, the presence of the embodiment of the alien arm was always accompanied by the embodiment of its passive and active movements. Furthermore, the delusion was significantly associated to primary proprioceptive deficits and to damages of the corona radiata and the superior longitudinal fasciculus. To conclude, we show that the pathological embodiment of an alien arm is well-characterized by recurrent and specific features and might be explained as a disconnection deficit, mainly involving white matter tracts. The proposed exhaustive protocol can be successfully employed to assess stroke-induced disorders of body awareness, unveiling even their more undetectable or covert clinical forms.

Delusions in a Sample of Patients with Schizophrenia and Bipolar Disorder: The same or different?

Abstract Background Growing evidences indicate that there is overlapping between schizophrenia (SCZ) and bipolar disorder (BP) in neurobiology, phenomenology or even in changing of diagnosis from schizophrenia to bipolar disorder or vice versa. Psychotic symptoms can be observed during manic or depressive episodes in bipolar disorder. While manic or depressive episodes can be observed between or during psychotic episodes in schizophrenia. Aim of the work To describe delusional types present in both groups of study sample: a group of patients with schizophrenia and a group of patients with bipolar disorder accompanied by psychotic features. Also to compare between types of delusions in patients with schizophrenia and patients with bipolar disorder accompanied by psychotic features. Patients and Methods total 80 patients (40 in group of Schizophrenia and 40 in group of bipolar disorder accompanied by psychotic features) were selected as convenient sampling from patients during the first two weeks of their admission in the Institute of Psychiatry, Ain Shams University Hospitals. Nature and types of the delusions were assessed by using Scale for the Assessment of Negative Symptoms (SANS), Positive and Negative Syndrome Scale (PANSS) and Young Mania Rating Scale (YMRS) in study period from 1st of October 2017 till 1st of April 2018. Results Delusion of persecution is the commonest delusion in group of SCZ (37.5%), while delusion of grandiosity is the commonest delusion in group of BP accompanied by psychotic features (32.5%). Monothematic delusions are doubling frequent in group of BP accompanied by psychotic features (75%) if it compared to group of SCZ (35%). Non systematized delusions are the dominant in group of SCZ (45%) while most delusions in other group are some systematized (45%). Delusions of most patients in group of SCZ are incongruent with mood (77.5%). While delusions of most patients in group of BP accompanied by psychotic features are congruent with mood (65%). The presence of delusion is positively correlated to higher score of: SANS (in both groups), PANSS (in both groups) and YMRS (in BP accompanied by psychotic features). Conclusion delusions of schizophrenia are different in nature and types when it compared to delusions of bipolar disorder.

FDG-PET in Cotard syndrome before and after treatment: can functional brain imaging support a two-factor hypothesis of nihilistic delusions?

ABSTRACTIntroduction: Cotard syndrome is a neuropsychiatric entity recognised by the presence of nihilistic delusions. Although different models have been proposed for the development of monothematic delusions, including Cotard syndrome, functional neuroanatomical models are lacking.Methods: A case report of a 19-year old male with autoimmune encephalitis and Cotard syndrome, in whom Positron Emission Tomography (18F-FDG-PET) scans were performed before and after successful treatment with electroconvulsive therapy (ECT), is presented. Literature review on brain imaging is provided to discuss a functional neuroanatomical model of Cotard syndrome, in accordance with the two-factor theory of delusions.Results: The patient’s 18F-FDG-PET showed marked insular and prefrontal metabolic abnormalities. Except for insular hypometabolism, metabolic abnormalities improved after ECT. Previously reported structural neuroimaging studies in Cotard syndrome showed a predominance of right hemisphere lesions, in which frontal lobes were more frequently involved, followed by parietal and temporal lesions. Functional neuroimaging studies reported abnormalities in frontoparietal circuits as well as midline structures included in the “default mode network”.Conclusions: Abnormalities in the functioning of the insular cortex and the prefrontal cortex could be related to the development of nihilistic delusions when a two-factor theory of delusions is considered.

NIHILISTIC DELUSION IN THE CONTEXT OF MAJOR DEPRESSIVE DISORDER WITH CATATONIC FEATURES IN A GERIATRIC PATIENT: A CASE REPORT AND REVIEW OF LITERATURE

NIHILISTIC DELUSION IN THE CONTEXT OF MAJOR DEPRESSIVE DISORDER WITH CATATONIC FEATURES IN A GERIATRIC PATIENT: A CASE REPORT AND REVIEW OF LITERATURE

Cognitive neuropsychiatric analysis of an additional large Capgras delusion case series

ABSTRACTIntroduction: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.

Monothematic delusion: A case of innocence from experience

ABSTRACTEmpiricists about monothematic delusion formation agree that anomalous experience is a factor in the formation of these attitudes, but disagree markedly on which further factors (if any) need to be specified. I argue that epistemic innocence may be a unifying feature of monothematic delusions, insofar as a judgment of epistemic innocence to this class of attitudes is one that opposing empiricist accounts can make. The notion of epistemic innocence allows us to tell a richer story when investigating the epistemic status of monothematic delusions, one which resists the trade-off view of pragmatic benefits and epistemic costs. Though monothematic delusions are often characterized by appeal to their epistemic costs, they can play a positive epistemic role, and this is a surprising conclusion on which, so I argue, all empiricists can agree. Thus, I show that all empiricists have the notion of epistemic innocence at their disposal.

Taxonomising delusions: content or aetiology?

ABSTRACTIntroduction: Many theoretical treatments assume (often implicitly) that delusions ought to be taxonomised by the content of aberrant beliefs. A theoretically sound, and comparatively under-explored, alternative would split and combine delusions according to their underlying cognitive aetiology.Methods: We give a theoretical review of several cases, focusing on monothematic delusions of misidentification and on somatoparaphrenia.Results: We show that a purely content-based taxonomy is empirically problematic. It does not allow for projectability of discoveries across all members of delusions so delineated, and lumps together delusions that ought to be separated. We demonstrate that an aetiological approach is defensible, and further that insofar as content-based approaches are plausible, it is only to the extent that they implicitly link content to aetiology.Conclusions: We recommend a more explicit focus on cognitive aetiology as the grounds for delusion taxonomy, even when that would undermine traditional content-based boundaries. We also highlight the iterative and complex nature of evidence about aetiologically grounded taxonomies.

SU34. A Systematic Review of Behavioral Research and Lesion Evidence for the 2-Factor Theory of Monothematic Delusions

SU34. A Systematic Review of Behavioral Research and Lesion Evidence for the 2-Factor Theory of Monothematic Delusions

Cotard Delusion in the Context of Schizophrenia: A Case Report and Review of the Literature

Background: The Cotard delusion (CD) is one of a variety of narrowly defined monothematic delusions characterized by nihilistic beliefs about the body’s existence or life itself. The presence of CD within the context of schizophrenia is rare (<1%), and remains understudied.Case: ‘Mr. C’ is a 58-year-old veteran with a prior diagnosis of schizophrenia, who presented with CD in the context of significant depression, suicidal ideation, violence, and self-harm behavior. He perseverated in his belief that he was physically dead and possessed by demons for several weeks. This delusion was reinforced by his religious belief that life was an attribute of God, and by inference, he as a human, was dead. His condition gradually improved over the course of treatment with Divalproex and quetiapine with discussions about the rationale for his belief. Upon discharge, Mr. C. demonstrated awareness of his fixation on death and an ability to redirect himself.Discussion: This case highlights the need to better understand the co-occurrence of CD in schizophrenia, their differentiation, the increased risk of violence and self-harm behavior in this presentation, and how specific events and religious factors can influence delusional themes of CD. Pharmacotherapy and aspects of cognitive-behavioral therapy may be effective in ameliorating these symptoms in CD.

Can delusions be understood linguistically?

ABSTRACTDelusions are widely believed to reflect disturbed cognitive function, but the nature of this remains elusive. The “un-Cartesian” cognitive-linguistic hypothesis maintains (a) that there is no thought separate from language, that is, there is no distinct mental space removed from language where “thinking” takes place; and (b) that a somewhat broadened concept of grammar is responsible for bestowing meaning on propositions, and this among other things gives them their quality of being true or false. It is argued that a loss of propositional meaning explains why delusions are false, impossible and sometimes fantastic. A closely related abnormality, failure of linguistic embedding, can additionally account for why delusions are held with fixed conviction and are not adequately justified by the patient. The un-Cartesian linguistic approach to delusions has points of contact with Frith’s theory that inability to form meta-representations underlies a range of schizophrenic symptoms. It may also be relevant to the nature of the “second factor” in monothematic delusions in neurological disease. Finally, it can inform the current debate about whether or not delusions really are beliefs.

Bodily ownership modulation in defensive responses: physiological evidence in brain-damaged patients with pathological embodiment of other's body parts.

Do conscious beliefs about the body affect defensive mechanisms within the body? To answer this question we took advantage from a monothematic delusion of bodily ownership, in which brain-damaged patients misidentify alien limbs as their own. We investigated whether the delusional belief that an alien hand is their own hand modulates a subcortical defensive response, such as the hand-blink reflex. The blink, dramatically increases when the threated hand is inside the defensive peripersonal-space of the face. In our between-subjects design, including patients and controls, the threat was brought near the face either by the own hand or by another person’s hand. Our results show an ownership-dependent modulation of the defensive response. In controls, as well as in the patients’ intact-side, the response enhancement is significantly greater when the threat was brought near the face by the own than by the alien hand. Crucially, in the patients’ affected-side (where the pathological embodiment occurs), the alien (embodied) hand elicited a response enhancement comparable to that found when the threat is brought near the face by the real hand. These findings suggest the existence of a mutual interaction between our conscious beliefs about the body and the physiological mechanisms within the body.

Phenomenological and neurocognitive perspectives on polythematic and monothematic delusions.

Phenomenological and neurocognitive perspectives on polythematic and monothematic delusions.