Biomedical subjects

Robyn Langdon

Publications and source records attributed to Robyn Langdon.

11 recordsLinked to original sources

PubMed2007

The defensive function of persecutory delusions: an investigation using the Implicit Association Test.

INTRODUCTION: Bentall and colleagues (Bentall & Kaney, 1996; Kinderman & Bentall, 1996, 1997) claim that persecutory delusions are constructed defensively, for the maintenance of self-esteem. A central prediction of their model is that such delusions will be associated with discrepancies between overt and covert self-esteem. METHODS: The present study employed a new methodology that has been widely used in investigations of implicit attitudes, the Implicit Association Test (IAT; Greenwald, McGhee, & Schwartz, 1998), to assess covert self-esteem and to test the above prediction. Overt self-esteem was assessed using the Rosenberg Self-Esteem Scale and an adjective self-relevance ratings measure. These measures were administered to 10 patients with acute persecutory delusions, 10 patients with remitted persecutory delusions, and 19 healthy control participants. RESULTS: Patients with persecutory delusions were found to have lower covert self-esteem (as assessed using the IAT) than healthy controls and patients with remitted persecutory delusions. On two measures of overt self-esteem, however, the persecutory deluded group did not differ significantly from the other groups once the effects of comorbid depression had been taken into account. CONCLUSIONS: These results are thus consistent with a model of persecutory delusions as serving the defensive function of maintaining self-esteem.

Adult↗

PubMed2006

Empathetic perspective-taking is impaired in schizophrenia: evidence from a study of emotion attribution and theory of mind.

INTRODUCTION: Schizophrenia and autism are clinically distinct yet both disorders are characterised by theory of mind (ToM) deficits. Autistic individuals fail to appreciate false beliefs, yet understand the causal connections between behavioural events and simple emotions. Findings of this type have promoted the view that ToM deficits in autism reflect a domain-specific difficulty with appreciating the representational nature of epistemic mental states (i.e., beliefs and intentions and not emotions). This study examines whether the same holds true for schizophrenia. METHODS: A picture-sequencing task assessed capacity to infer false beliefs in patients with schizophrenia and healthy controls. To assess emotion attribution, participants were shown cartoon strips of events likely to elicit strong emotional reactions in story characters. Characters' faces were blanked out. Participants were instructed to think about how the characters would be feeling in order to match up the cards depicting facial affect appropriately. Participants later named emotions depicted in facial affect cards. RESULTS: Patients were as capable as controls of identifying cartoon facial expressions, yet had greater difficulties with: (a) attributing emotions based on circumstances; and (b) inferring false beliefs. CONCLUSIONS: Schizophrenia patients, unlike autistic individuals, suffer a domain-general difficulty with empathetic perspective-taking that affects equally their appreciation of other people's beliefs, percepts, and emotions.

Adult↗

PubMed2006

Need for closure, jumping to conclusions, and decisiveness in delusion-prone individuals.

Need for closure refers to a motivated need for certainty. Jumping-to-conclusions bias refers to the gathering of minimal data when making overconfident probabilistic judgments. Both constructs have been associated independently with delusion-proneness. Fifty-eight nonclinical adults were assessed for jumping-to-conclusions bias using an experimental reasoning task, and need for closure, decisiveness concerning real-life dilemmas, and delusion-proneness using questionnaires. Delusion-proneness was associated independently with need for closure and jumping-to-conclusions bias, with no evidence of a direct relationship between the latter two. These results discount the view that need for closure motivates a jumping-to-conclusions bias, leading, in turn, to delusion-proneness. The various facets of need for closure proved to be independent; while intolerance of ambiguity correlated positively with delusion-proneness, decisiveness correlated negatively. The finding that delusion-prone individuals are more indecisive in everyday life was replicated using different scales. Delusion-proneness is associated independently with jumping-to-conclusions bias on experimental reasoning tasks, intolerance of ambiguity, and indecision concerning real-life dilemmas.

Adolescent↗

PubMed2006

The persecutory ideation questionnaire.

We report the development and evaluation of a brief questionnaire measure of persecutory ideation, the Persecutory Ideation Questionnaire (PIQ). Our approach was theoretically driven in that the PIQ was constructed in accordance with comprehensive definitional considerations and criteria set out by . Sixty-six more general paranoia-related items were accumulated, and 10 independent raters sorted the items into two sets, "persecutory ideation" and "other." An 80% agreement criterion was set, resulting in 10 persecutory ideation items. The PIQ was evaluated with a nonclinical and a clinical sample. In both samples, it was shown to have excellent reliability (internal consistency) and excellent convergent validity as a measure of certain aspects of general paranoid ideation. Finally, the PIQ shared unique variance with severity of persecutory delusions in the clinical group, providing good criterion validity for the PIQ as a measure of specifically persecutory ideation, rather than paranoia in general.

Adolescent↗

PubMed2005

Paranoia, persecutory delusions and attributional biases.

An influential model of persecutory delusions put forward by Bentall and colleagues hypothesizes that persecutory-deluded patients avoid the activation of negative self-beliefs by making externalising, personalising attributions for negative events. The first study reported here used a new instrument for the measurement of persecutory ideation, the Paranoid, Persecutory and Delusion-Proneness Questionnaire, to investigate whether attributional biases are associated with subclinical persecutory ideation. The second study extended this investigation by re-examining associations between attributional biases and persecutory delusions. Both studies used the Internal, Personal and Situational Attributions Questionnaire to measure attributional style. No evidence was found for a connection between attributional biases and subclinical persecutory ideation. Furthermore, there was no support for an association between persecutory delusions and an externalising bias, and only marginal support for the hypothesized relationship between persecutory delusions and a personalising bias. These results suggest that the putative link between persecutory ideation and attributional biases only manifests (if at all) when persecutory ideation is of delusional intensity, and that it is confined to a personalising bias.

Adolescent↗

PubMed2005

Externalizing and personalizing biases in persecutory delusions: the relationship with poor insight and theory-of-mind.

The presence of externalizing bias (EB) for negative events together with personalizing bias (PB) (a bias to blame others rather than circumstances) may jointly constitute a vulnerability to develop persecutory delusions (PDs). Whereas EB purportedly serves to defend a vulnerable self-concept by avoiding negative self-attributions and might therefore exacerbate poor insight, PB may reflect cognitive deficits, including theory-of-mind impairment. We investigated these proposals in 34 schizophrenic patients with a history of PDs and 21 healthy controls. Patients with moderate- to severe-PDs and patients without a current PD showed excessive EB which was, surprisingly, absent in patients with mild persecutory delusions (mild-PDs). That EB might wax and wane with fluctuating delusional intensity was interpreted in accord with a new dynamic model of attribution self-representation cycles. As predicted, EB exacerbated poor insight. However, counter to predictions, theory-of-mind impairment did not increase PB, which was marked in all participants, whether clinical or non-clinical; instead, theory-of-mind impairment was also correlated with poor insight. Our findings indicate multiple pathways to poor insight, one of which is a theory-of-mind difficulty, impairing the capacity to simulate other perspectives for the purpose of critically evaluating one's own beliefs and circumstances.

Adult↗

PubMed2005

Attentional orienting triggered by gaze in schizophrenia.

The ability to detect the direction of another person's gaze and to shift our own attention reflexively in the same direction facilitates the sharing of attention with other people. Such sharing of attention would seem critical for the maintenance of normal social cognition. Social cognition is severely impaired in people with schizophrenia. So, we used spatial cuing paradigms to investigate reflexive (Experiment 1) and controlled (Experiment 2) attentional orienting triggered by gaze in schizophrenia. In Experiment 1, 30 patients and 24 controls detected targets appearing right or left of a central image of a head turned right, left, or straight-ahead. These gaze-cues were non-predictive. Patients, but not controls, showed a significant congruency advantage at 100 ms SOA. The congruency advantage was similar in patients and controls at 300-800 ms SOA. In Experiment 2, 20 patients and 24 controls detected targets 300-800 ms after a central gaze-cue that pointed away from the target on 80% of trials. Controls, but not patients, were able to reverse the reflexive congruency advantage at 800 ms SOA. This study provides the first evidence that people with schizophrenia show abnormally sensitive gaze-triggered reflexive orienting. Findings are discussed in light of recent neuroimaging work investigating the neural basis of social orienting and social cognition.

Adult↗

PubMed2005

Schizophrenia, theory of mind, and persecutory delusions.

INTRODUCTION: There is already a substantial body of evidence supporting Frith's (1992) theory that theory of mind (ToM) is impaired in people with schizophrenia. However, a specific relationship between impaired ToM and paranoid delusions, while intuitively reasonable, has only been demonstrated in two studies to date. METHODS: A total of 25 participants with schizophrenia were classified as paranoid or nonparanoid and compared with 38 healthy controls on a variety of ToM tasks. These tasks included verbal and nonverbal, and first and second order ToM tasks. RESULTS: Participants with schizophrenia performed significantly more poorly than healthy controls on both the first and second order verbal ToM tasks but not on the nonverbal ToM tasks. However, the ToM deficit was only observed for those participants with schizophrenia who had persecutory delusions. There was also a strong relationship observed between the severity of persecutory delusions and length of illness. CONCLUSIONS: This study represents only the third demonstration of a specific link between paranoid delusions and ToM impairment. Reasons why previous findings on this issue have been so inconsistent are considered. Further research is needed to explore the relationships among paranoia, ToM, and length of illness.

Journal Article↗

PubMed2005

"Sleights of mind": delusions, defences, and self-deception.

Two different modes of theorising about delusions are explored. On the one hand is the motivational approach, which regards delusions as serving a defensive, palliative, even potentially adaptive function. On the other, is the cognitive deficit approach, which conceptualises delusions as explicitly pathological, involving abnormalities in ordinary cognitive processes. The former approach, prominently exemplified by the psychoanalytic tradition, was predominant historically, but has been challenged in recent years by the latter. Some grievances against psychoanalytic theory are briefly discussed, and it is argued that although the reasons for psychoanalysis falling into scientific disrepute are partly justified, the psychodynamic notion that motivation has access to the mechanisms of belief formation is of potentially crucial theoretical utility. A variety of possible syntheses of the two theoretical modes are therefore explored, in the belief that the most comprehensive account of delusions will involve a theoretical unification of both styles of explanation. Along the way, an attempt is made to locate the notions delusion, defence, and self-deception in a shared theoretical space.

Journal Article↗

PubMed2004

Recognition of metaphor and irony in young adults: the impact of schizotypal personality traits.

Patients with schizophrenia demonstrate two dissociable impairments of pragmatic language comprehension: (1) an insensitivity to irony, which is associated with poor theory-of-mind (i.e. a difficulty with inferring other people's thoughts); and (2) poor recognition of metaphors, which may reflect degraded semantics. This study investigated whether non-clinical high-schizotypal adults show similar impairments of pragmatic language. Thirty-six university students completed the Raine Schizotypal Personality Questionnaire, the Wechsler Memory Scale Logical-Memories subtest, Raven's Progressive Matrices and a story comprehension task that tested the ability to discriminate between incongruous statements and appropriate uses of ironical, metaphorical or literal speech. Counter to the pattern found for patients, high-schizotypal adults were just as capable as low-schizotypal adults of identifying appropriate metaphors, suggesting a discontinuity between schizophrenia and schizotypy for the metaphor-recognition problem. This study's finding of intact metaphor recognition in high-schizotypal adults contrasts with previous findings of poor proverb comprehension in these individuals and is interpreted in terms of different semantic processes required for recognizing and interpreting metaphors. Consistent with the pattern found for patients, high-schizotypal adults were significantly impaired in their ability to appreciate when a literally contradictory utterance could be interpreted as ironical, suggesting continuity between schizophrenia and schizotypy for the irony-appreciation problem.

Adolescent↗

PubMed2003

Repetition blindness for words yet repetition advantage for nonwords.

Accuracy of report of words in a rapidly presented sequence is reduced if 1 word is a repetition of a previous word. This is repetition blindness. If, however, the items are pronounceable nonwords, or pseudohomophones, repetition improves recall. A repetition advantage for nonwords also occurs when subjects merely count the items or when the item between the critical nonwords is a familiar word. Familiarizing subjects with the nonwords improved the level of recall but did not affect the repetition advantage. These results are considered in relation to token individuation and other accounts of repetition blindness. The findings suggest that for identical linguistic stimuli the types bound to episodic memory tokens that are vulnerable to repetition blindness are lexical units.

Adolescent↗