Attributional biases in paranoid schizophrenia: further evidence for a decreased sense of self-causation in paranoia

Attributional biases are assumed to be part of the pathogenesis of persecutory delusions. The aim of the present study was to explore whether such biases are confined to current paranoid delusions or related to other positive symptoms as well. Another goal was to investigate whether current paranoid schizophrenia patients only show an exaggerated personalizing bias for negative events (i.e. personalizing blame) or also tend to externalize responsibility for positive events (i.e. decreased sense of self‐causation). The Internal, Personal and Situational Attributions Questionnaire (IPSAQ) was administered to 29 schizophrenia patients (10 with current paranoia), 26 psychiatric patients (OCD) and 33 healthy controls. Acutely paranoid patients made fewer internal attributions for positive and negative events, thus replicating a previously reported decreased sense of self‐causation. This kind of attributional style was related to acute positive symptomatology, but not to persecutory beliefs in particular. No evidence was found for a relationship between personalizing blame and the severity of current persecutory beliefs. An analysis of the narrative causal statements of the IPSAQ revealed that paranoid patients more often made external‐situational attributions particularly for positive events. Both psychiatric groups gave significantly more mono‐causal explanations for events than healthy controls.