Why do people with delusions fail to choose more realistic explanations for their experiences? An empirical investigation

Delusions can be viewed as explanations of experiences,. By definition, the experiences are insufficient to merit the delusional explanations. So why have delusions been accepted rather than more realistic explanations? The authors report a study of alternative explanations in 100 individuals with delusions. Patients were assessed on the following criteria: symptom measures, the evidence for the delusions, the availability of alternative explanations, reasoning, and self-esteem. Three quarters of the patients did not report any alternative explanation for the experiences on which the delusions were based. These patients reported significantly more internal anomalous experiences and had a more hasty reasoning style than patients who did have alternative explanations available. Having doubt in a delusion, without an alternative explanation, was associated with lower self-esteem. Clinicians will need to develop plausible and compelling alternative accounts of experience in interventions rather than merely challenge patients' delusional beliefs.     

On abductive inference and delusional belief: Why there is still a role for patient experience within explanations of Capgras delusion

This paper aims to examine critically the explanatory model of delusional belief presented in Coltheart, Menzies, and Sutton's (2010) paper, “Abductive Inference and Delusional Belief”. The authors acknowledge that certain aspects of the model are speculative. In return, I speculate over the likelihood that the model's emphasis on subpersonal processing adequately and coherently explains the symptoms (as best we know them) of patients with delusional misidentification (specifically, the Capgras delusion) and nondeluded equivalent patient groups. In addition, I offer an account of the Capgras delusion that is compatible with many of the tenets of Coltheart et al.'s model, but which preserves an important explanatory role for patient experience absent, and erroneously so, I contend, from the aforementioned model. The more integrated explanation I am proposing here also provides a number of pertinent empirical questions and testable hypotheses that could inform future models of delusional belief.     

The “Truman Show” delusion: Psychosis in the global village

Introduction. We report a novel delusion, primarily persecutory in form, in which the patient believes that he is being filmed, and that the films are being broadcast for the entertainment of others.

Methods. We describe a series of patients who presented with a delusional system according to which they were the subjects of something akin to a reality television show that was broadcasting their daily life for the entertainment of others. We then address three questions, the first concerning how to characterise the delusion, the second concerning the role of culture in delusion, and the third concerning the implications of cultural studies of delusion for the cognitive theory of delusion.

Results. Delusions are both variable and stable: Particular delusional ideas are sensitive to culture, but the broad categories of delusion are stable both across time and culture. This stability has implications for the form a cognitive theory of delusion can take.

Conclusions. Cultural studies of delusion have important contributions to make to the cognitive theory of delusion.     

The erotetic theory of delusional thinking

Introduction. In this paper, we argue for a novel account of one cognitive factor implicated in delusional cognition. According to the erotetic theory of delusion we present, the central cognitive factor in delusion is impaired endogenous question raising.

Method. After presenting the erotetic theory, we draw on it to model three distinct patterns of reasoning exhibited by delusional and schizophrenic patients, and contrast our explanations with Bayesian alternatives.

Results. We argue that the erotetic theory has considerable advantages over Bayesian models. Specifically, we show that it offers a superior explanation of three phenomena: the onset and persistence of the Capgras delusion; recent data indicating that schizophrenic subjects manifest superior reasoning with conditionals in certain contexts; and evidence that schizophrenic and delusional subjects have a tendency to “jump to conclusions.” Moreover, since the cognitive mechanisms we appeal to are independently motivated, we avoid having to posit distinct epistemic states that are intrinsically irrational in order to fit our model to the variety of data.

Conclusion. In contrast to Bayesian models, the erotetic theory offers a simple, unified explanation of a range of empirical data. We therefore conclude that it offers a more plausible framework for explaining delusional cognition.     

妄想、抑郁与自杀行为的关系

目的：探讨妄想、抑郁与自杀行为的关系。方法：对100例妄想性抑郁症与198例非妄想性抑郁症自杀行的相对危险性是非妄想性抑郁症的3．45倍。结论：妄想性抑郁症的自杀行为较非妄想性抑郁症多见。     

Cotard delusion after brain injury.

A right-handed young man with contusions affecting temporo-parietal areas of the right cerebral hemisphere and some bilateral frontal lobe damage became convinced that he was dead (the Cotard delusion), and experienced difficulties in recognizing familiar faces, buildings and places, as well as feelings of derealization. Neuropsychological investigation while these symptoms were resolving revealed impairment on face processing tests. We suggest that these impairments contributed to his Cotard delusion by heightening feelings of unreality, and that the underlying pathophysiology and neuropsychology of the Cotard delusion may be related to other problems involving delusional misidentification.     

Bayesian accounts and black swans: Questioning the erotetic theory of delusional thinking

Parrott and Koralus argue that a particular cognitive factor – “impaired endogenous question raising” – offers a parsimonious account of three delusion-related phenomena: (1) the development of the Capgras delusion; (2) evidence that patients with schizophrenia outperform healthy control participants on a conditional reasoning task; and (3) evidence that deluded individuals “jump to conclusions”. In this response, I assess these claims, and raise my own questions about the “erotetic” theory of delusional thinking.     

Visual processing in patients with Frégoli syndrome

We investigated four paranoid schizophrenic patients diagnosed with Frégoli delusion, and four matched psychotic controls. Neuropsychological testing included visual and verbal recognition memory, in addition to a comparison of left and right hemispheric processing of two different classes of stimuli, animate and inanimate objects. Performance on the recognition memory test failed to discriminate between the two psychotic groups on the basis of facial recognition, however, the patients with Frégoli delusion failed to show the right hemisphere processing advantage for the animate class of stimuli found for the set of norms and also present in the psychotic control group. These results are discussed in the context of both current theories of the delusional misidentification syndromes in general, and models of facial recognition in particular.     

Measurement and modification of delusional beliefs

It has been proposed that delusional thinking may be on a continuum with normal behavior and can be assessed by taking account of factors such as the client's degree of belief conviction or the extent of preoccupation with the belief. In our research a number of measures were used to assess the delusional thinking of people diagnosed as schizophrenic. Two interventions were used: (a) a structured verbal challenge and (b) a reality test in which the belief was subject to an empirical test. We used a multiple-baseline, across-subjects design. Of the 6 clients, 2 completely rejected their beliefs, and 3 others significantly reduced their belief conviction. Maintenance was good, and there was evidence that the intervention had enabled 5 of the 6 clients to effectively regulate their delusional thinking.     

妄想性与非妄想性抑郁症的临床对照分析

目的：探讨妄想性抑郁症的临床特征。方法：对100例妄想性抑郁症与198年非妄想性性抑郁症进行临床对照分析。结果：妄想性抑郁症焦虑、激越、自责自罪，绝望，自杀行为的出现频率较高，往往需联合用药方能奏效。结论：妄想性抑郁症与非妄想性抑郁症在症状学及治疗学方面存在差异。     

Developing hypnotic analogues of clinical delusions: Mirrored-self misidentification

Introduction. Despite current research interest in delusional beliefs, there are no viable models for studying delusions in the laboratory. However, hypnosis offers a technique for creating transient delusions that are resistant to challenge. The aim of this study was to develop an hypnotic analogue of one important delusion, mirrored-self misidentification.

Methods. Twelve high hypnotisable participants received an hypnotic suggestion to see either a stranger in the mirror, a mirror as a window, or a mirror as a window with a view to a stranger. Participants’ deluded beliefs were challenged, and following hypnosis, Sheehan and McConkey's (1982) Experiential Analysis Technique was used to explore participants’ phenomenological experience of the delusion.

Results. The majority of participants did not recognise their reflection in the mirror, described the person in the mirror as having different physical characteristics to themselves, and maintained their delusion when challenged.

Conclusions. The hypnotic suggestion created a credible, compelling delusion with features strikingly similar to clinical cases of mirrored-self misidentification. Our findings suggest that Factor 2 within Langdon and Coltheart's (2000) two-factor framework may involve a lowering of the criteria used to accept or reject delusional hypotheses.     

Mirror agnosia and the mirrored-self misidentification delusion: A hypnotic analogue

Introduction. Mirrored-self misidentification is the delusional belief that one's reflection in the mirror is a stranger. Current theories suggest that one pathway to the delusion is mirror agnosia (a deficit in which patients are unable to use mirror knowledge when interacting with mirrors). This study examined whether a hypnotic suggestion for mirror agnosia can recreate features of the delusion.

Method. Ten high hypnotisable participants were given either a suggestion to not understand mirrors or to see the mirror as a window. Participants were asked to look into a mirror and describe what they saw. Participants were tested on their understanding of mirrors and received a series of challenges. Participants then received a detailed postexperimental inquiry.

Results. Three of five participants given the suggestion to not understand mirrors reported seeing a stranger and maintained this belief when challenged. These participants also showed signs of mirror agnosia. No participants given the suggestion to see a window reported seeing a stranger.

Conclusion. Results indicate that a hypnotic suggestion for mirror agnosia can be used to recreate the mirrored-self misidentification delusion. Factors influencing the effectiveness of hypnotic analogues of psychopathology, such as participants’ expectations and interpretations, are discussed.     

Delusional Misidentification of Inanimate Objects: A Literature Review and Neuropsychological Analysis of Cognitive Deficits in Two Cases

Following a brief review of the literature on Delusions of Inanimate Doubles (DID), compared with other similar delusions, two cases are presented. Each completed a battery of tests designed to explore their cognitive abilities. In both cases, familiar and unfamiliar face-processing skills remained intact and word memory was unaffected. Their abilities to identify famous buildings and recognise unfamiliar houses were impaired. We propose that an extension of Ellis and Young's (1990) account of Capgras delusion can explain the cognitive impairments in case of DID. A comparison of the hypotheses of Staton et el. (1982), Ellis and Young (1990), and Van Lancker (1991) is also made. The last two have obvious similarities and seem to provide the best general approach. Finally, we caution the need to consider how a mood of suspiciousness may be needed to distort attribution processes that sustain delusional thinking.     

Persecutory delusions: developing the understanding of belief maintenance and emotional distress.

BACKGROUND: The objective of the study was to develop the cognitive understanding of persecutory delusions. It was hypothesized that safety behaviours contribute to the persistence of persecutory delusions by preventing disconfirmation. It was further hypothesized that emotional distress is associated with aspects of the content of delusions. An investigation was designed to establish whether individuals with persecutory delusions use safety behaviours, and to test predicted associations between delusion content and emotional distress. METHOD: A cross-sectional investigation was conducted on 25 individuals with persecutory delusions. A detailed assessment was made of the presence of safety behaviours, the content of delusions and emotional distress. RESULTS: All participants had used at least one safety behaviour in the last month, most typically avoidance. Higher levels of anxiety were associated with greater use of safety behaviours. New data were obtained on the content of persecutory delusions. Aspects of the content of the delusions were associated with levels of depression, self-esteem, anxiety and delusional distress. CONCLUSIONS: Individuals with persecutory delusions use safety behaviours. The findings may develop the understanding of delusion persistence, acting upon delusions and the negative symptoms of schizophrenia. There are implications for cognitive interventions for psychosis. Support was also found for the hypothesis that emotional distress is linked to the content of delusional beliefs; it is speculated that prior emotional distress influences the content of delusions, and that delusion content in turn influences levels of emotional distress.     

SOME THOUGHTS ON SCHREBER (AND FREUD): DEPRESSION, PARANOIA AND A DELUSIONAL SYSTEM

ABSTRACT Freud's paper on Daniel Paul Schreber is a seminal psychoanalytic text (Freud 1911). In it, he sets out his argument that Schreber's paranoid delusions arose from repressed homosexuality. This paper reconsiders the case of Schreber from a contemporary perspective chiefly by studying, as did Freud, Schreber's autobiographical Memoirs of My Nervous Illness (Schreber 1903), but also by drawing upon more recent biographical information. It follows the view put forward by Lothane (1992), and recently elaborated by Steiner (2004), that Schreber's illness was originally depressive in nature, and then progressed to paranoia and finally to a settled delusional system. It reviews many of Freud's insights, contending that although some, such as his understanding of the mechanism of paranoia and the manner by which a delusion of persecution is converted into a religious delusion of grandeur, have stood the test of time, others, such as the causal relationship he proposes between homosexuality and paranoia, do not.     

Models of confabulation: a critical review and a new framework

Confabulation can be defined as statements or actions that involve distortions of memories. This paper reviews current theories of confabulation focusing on source monitoring, temporal-context, and retrieval theories. The attributes and criticisms of these three models are discussed. From this review, a three-factor cognitive-neuropsychological framework is proposed, which can be used to explain the variable symptoms of confabulation. The framework takes its basis from the Langdon and Coltheart (2000a, 2000b) cognitive model of delusional belief formation. The model suggests that two deficits are likely in most cases of confabulation - an executive control retrieval deficit and an evaluation deficit. It also takes into consideration how the general organization of the autobiographical memory store and a person's individual emotional/motivational biases can influence confabulatory symptoms and content. This is an overarching framework that can be used to model confabulations, and it builds upon links between delusions and confabulation.     

Visual Processing in Patients with Fregoli Syndrome

W e investigated four paranoid schizophrenic patients diagnosed with Fregoli delusion, and four matched psychotic controls. Neuropsychological testing included visual and verbal recognition memory, in addition to a comparison of left and right hemispheric processing of two different classes of stimuli, animate and inanimate objects. Performance on the recognition memory test failed to discriminate between the two psychotic groups on the basis of facial recognition, however, the patients with Fre goli delusion failed to show the right hemisphere processing advantage for the animate class of stimuli found for the set of norms and also present in the psychotic control group. These results are discussed in the context of both current theories of the delusional misidentification syndromes in general, and models of facial recognition in particular.     

Autonomic responses to familiar faces without autonomic responses to familiar voices: Evidence for voice-specific Capgras delusion

Introduction: Patients with Capgras delusion believe that certain individuals have been replaced by duplicates. Unlike normal people, these patients also show reduced autonomic responses to familiar faces, indicating the possibility that it is the covert processes of recognition that are impaired (Ellis, et al., 1997). It has been suggested that such patients would show normal autonomic responses to voices. An auditory parallel of this typical delusion, therefore, is theoretically possible. That is, a delusion whereby mis-recognition of the voice produces the delusional belief of duplication. Such a delusion would only occur in situations where the person is recognised by voice only; and so, even where it does exist, it would often escape diagnosis. Method: We present here a case, H.L., of what appears to be the Capgras delusion for voices in a sighted person. This case was investigated using standard skin conductance tests for face and voice recognition. Results: Consistent with this diagnosis, H.L. displays normal autonomic responses for faces but reduced autonomic responses for famous voices. Discussion: H.L. represents a previously unreported form of Capgras delusion and, further, shows dissociation between autonomic responses to faces and voices. Implications for cognitive models of person recognition are discussed.     

The contribution of metaphor and metonymy to delusions

This article investigates the possible role of metaphorical thinking in psychotic delusions. Twenty‐five participants with delusions were asked to give an account of how their ideas had formed and to describe recent experiences relevant to their delusional beliefs. The data suggest that for some participants there may have been a crucial period when the person has unusual experiences, psychosocial difficulties, and made attempts involving metaphor/metonymy to understand these experiences. Furthermore, some participants reported very recent unusual experiences using metaphorical terms, and we speculate on the possibility that the content of the metaphors contributes to a continuation of psychotic experience. The data form a series of case illustrations and are exploratory. No generalizations can be made, but the presence of significant metaphors and metonymy in 11 out of 25 case histories suggests the process may be an important one. We end by outlining a theoretical model of how metaphors might contribute to the formation of delusions: it is suggested that delusional statements are intended to be literal statements, but report on experiences transformed by metaphorical meaning. This transformation involves the ‘fusion’ of conceptual domains.     

Delusional parasitosis: a rare cause of pruritus in hemodialysis patients

Uremic pruritus is a common symptom in patients undergoing hemodialysis (HD) or peritoneal dialysis, but its exact pathogenesis remains rather unclear. However, severe or "intractable" pruritus may be the manifestation of another underlying disease or disorder other than uremia. Delusional parasitosis, or Ekbom syndrome, is a rare psychiatric disorder characterized by the false conviction of being infested with parasites, and it can be primary, or secondary to several medical and psychiatric disorders. We report 2 elderly HD patients who presented one after another, with delusional parasitosis. At some point in time, the delusional beliefs of the first patient were adopted by the second patient who was waiting to start his HD session on the same bed and HD machine, on a subsequent shift. They were both diagnosed with Ekbom syndrome and described as having monosymptomatic hypochondriac delusion. They were both prescribed antipsychotic medications. During follow-up they admitted feeling better than before; however, they remained concerned about the "insects/parasites."