Attributional style, defensive functioning and persecutory delusions: Symptom-specific or general coping strategy?

Objective. Previous research has suggested that individuals with persecutory delusions use an exaggerated self-serving bias to protect themselves from real or delusional threats to their underlying self-concept. However, the research to date has been inconsistent thereby limiting the conclusion that can be inferred. A possible explanation for these discrepant findings may be due to the use of measures with questionable validity and reliability such as the Attributional Style Questionnaire and the Rosenberg Self-Esteem Inventory. The present study aims to re-examine this theory using an improved methodology to determine whether defensive functioning is a defining feature of persecutory delusions. Design and methods. Thirty-five participants suffering from recent onset psychosis were assessed in a cross-sectional design. Three tests of attributional style were used, two overt measures (Attributional Style Questionnaire, ASQ; and the Internal Personal and Situational Attributions Questionnaire, IPSAQ) and one covert measure (Pragmatic Inference Test). Self-esteem was measured using the Rosenberg Self-Esteem Inventory (SEI) and a semi-structured interview (Self-Evaluation and Social Support interview - schizophrenia version). Results. A self-serving bias (SSB) was found in the total sample using the ASQ but not specifically in participants with persecutory delusions. In addition, the SSB was unrelated to levels of paranoia on any measure of attributional style. An underlying depressive attributional style was found in both subjects with and without persecutory delusions, but was not associated with levels of paranoia. Lower positive and higher negative self-esteem was associated with increased paranoia and was associated with a SSB. © 2006 The British Psychological Society.