Biomedical subjects

Ryan McKay

Publications and source records attributed to Ryan McKay.

7 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

Lithium alters regional rat brain myo-inositol at 2 and 4 weeks: an ex-vivo magnetic resonance spectroscopy study at 18.8 T.

Lithium has been the mainstay of treatment for bipolar disorder. Early studies suggest that lithium acts via inositol depletion. This study assesses the effect of 1, 2 and 4 weeks of lithium treatment on myo-inositol concentrations across several brain regions. Thirty-six Sprague-Dawley rats were treated for 2 weeks with an intraperitoneal injection of either 1 mmol/kg/day, twice daily lithium chloride (n=18) or placebo (2 ml/kg of saline) (n=18). The rats were separated into three groups: 1 week, 2 weeks and 4 weeks. Brains were dissected into prefrontal, temporal and occipital cortical areas, as well as hippocampus, and analyzed at 18.8 T. Myo-inositol was quantified using the Chenomx Profiler software. Lithium did not alter myo-inositol concentrations at 1 week. A significant reduction exists in myo-inositol concentrations in lithium-treated rats at 2 and 4 weeks, across all four brain regions. Studies suggest brain region-specific alterations in myo-inositol concentrations among bipolar patients. Our findings suggest that lithium-induced reduction of myo-inositol is more global.

Animals↗

PubMed2006

Attributional style in a case of Cotard delusion.

Young and colleagues (e.g. Young, A. W., & Leafhead, K. M. (1996). Betwixt life and death: case studies of the Cotard delusion. In P. W. Halligan & J. C. Marshall (Eds.), Method in madness: Case studies in cognitive neuropsychiatry. Mahway, NJ: Lawrence Erlbaum Associates.) have suggested that cases of the Cotard delusion (the belief that one is dead) result when a particular perceptual anomaly (caused by a disruption to the affective component of visual recognition) occurs in the context of an internalising attributional style. This hypothesis has not previously been tested directly. We report here an investigation of attributional style in a 24-year-old woman with Cotard delusion ("LU"). LU's attributional style (and that of ten healthy control participants) was assessed using the Internal, Personal and Situational Attributions Questionnaire (Kinderman, P., & Bentall, R. P. (1996). A new measure of causal locus: the internal, personal and situational attributions questionnaire. Personality and Individual Differences, 20(2), 261-264.). LU showed a significantly greater proportion of internalising attributions than the control group, both overall and for negative events specifically. The results obtained thus support an association of Cotard delusion with an internalising attributional style, and are therefore consistent with the account of Young and colleagues. The potential brain basis of Cotard delusion is discussed.

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

"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↗