هذیان های گزند و خود: بررسی ضمنی و صریح اعتماد به نفس

Persecutory delusions are proposed to be a defence against low self-esteem reaching conscious awareness (Bentall, Corcoran, Howard, Blackwood, & Kinderman, 2001). Key predictions of this proposal are that individuals with persecutory delusions will have lower implicit self-esteem and equivalent levels of explicit self-esteem compared to healthy controls. This study aims to test the predictions regarding implicit and explicit self-esteem in people with persecutory delusions. Of 22 people screened for persecutory delusions, 16 were recruited to the study. 20 healthy control participants were recruited. The Implicit Association Test was used to measure implicit self-esteem and the Rosenberg self-esteem scale was used to assess explicit self-esteem. Positive and negative self and other schemas were also assessed using the Brief Core Schema Scales. People with persecutory delusions had positive implicit self-esteem, comparable to that of the control group. Explicit self-esteem was lower for the persecutory delusion group, but was associated with increased depression and anxiety. Negative self and other schemas were higher in the clinical group. The results do not support the contention that persecutory delusions defend against negative self-representations and low self-esteem reaching conscious awareness. Non-defensive cognitive models are discussed as an alternative way of understanding persecutory delusions.

Persecutory delusions are characterised by the belief that others intend psychological, physical or social harm to the self (Freeman & Garety, 2000). Cognitive models have therefore focused on beliefs about the self and others, in order to understand the formation and maintenance of persecutory delusions. The attribution self-representation model proposes that individuals with persecutory delusions have latent negative beliefs about the self, and that the persecutory delusion provides a defence against low self-esteem reaching conscious awareness (Bentall, Corcoran, Howard, Blackwood, & Kinderman, 2001). To date the research evidence supporting this contention is inconclusive (Garety & Freeman, 1999), which is partly due to methodological difficulties measuring implicit self-esteem. The focus of this study is on the investigation of implicit and explicit self-esteem in people with persecutory delusions, in order to test the defensive hypothesis, as well as overcoming some of the methodological problems in the assessment of implicit self-esteem.

Statistical analysis was conducted with SPSS, version 15.0. A priori power calculations (based on data from McKay et al. (2007) & Moritz et al. (2006)) indicated that the required sample size for each group was between 4 and 22 participants in order to achieve a power level (1-β) of between .96 and .98. Data from 16 clinical and 20 control participants was analysed in this study. A minimum statistical level of .05 was set for all tests.