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UBC Theses and Dissertations

Symptom-related attributional biases in schizophrenia and bipolar disorder Sanford, Nicole Alexandra


Impairments in social cognition are known to have severe impacts on functional outcome in schizophrenia. Attributional biases (i.e., biases towards assigning blame/credit to oneself, other people, or to the situation) are of particular interest due to their direct relevance to paranoid delusions and potential implication in cognitive-based treatments. A "defense" model of paranoid delusions proposed by Bentall, Kinderman, and Kaney (1994) suggests that paranoid individuals possess an extreme self-serving bias, with a specific tendency to blame other people as opposed to the situation (i.e., personalizing bias). In addition, an inability to integrate belief-disconfirming information is thought to underlie the fixedness of delusions. However, these biases have not been investigated simultaneously to check for additive or multiplicative effects on associations with symptoms. Moreover, previous studies have failed to take into account the heterogeneity of the symptoms of psychosis. The present research employed structural equation modelling and constrained principal component analysis in schizophrenia patients, bipolar disorder patients, and healthy individuals to examine the extent to which group differences and symptom severity could predict patterns of responding on a novel attributional bias task, designed to assess an individual's ability to integrate contextual information in conjunction with attributional reasoning. In line with the defense model of paranoia, it was predicted that schizophrenia patients with severe paranoid delusions would display enhanced self-serving and personalizing biases. However, no differences between diagnostic- or symptom-based participant groups were found. Conversely, the severity of symptoms of overactive disorganization in schizophrenia and bipolar disorder patients predicted higher situation attributions and self-blame (specifically when such attributions were unsupported by the available evidence), while higher depression in healthy participants was negatively related to situation attributions and lower self-credit. These findings suggest that non-self-serving bases may be non-specifically related to high psychopathology, while an ability to integrate socially-relevant contextual information to consider other people’s roles in events may be reduced in overactive disorganization in mental illness, and is negatively related to depression in healthy individuals. The absence of noticeable group differences in attributional biases illustrates the importance of employing a multivariate symptom-based approach when studying complex cognitive processes in psychosis.

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