Background: The Pictorial Representation of Illness and Self Measure (PRISM) is a recently developed tool purported to assess burden of suffering due to illness. The nature of the PRISM task suggests a conceptual link to the illness self-schema construct hypothesised to be present in some individuals with chronic illness. This study investigates the relationship between PRISM and schema as measured by cognitive bias. Methods: 43 patients with systemic lupus erythematosus (SLE) completed an information-processing task involving endorsement of positive and negative illness words as descriptors of themselves, followed by free recall of the words. The outcome measures were endorsement and recall bias for negative illness words. Patients also completed the PRISM task and were assessed on other physical and psychological variables. Results: PRISM did not correlate significantly with age, depression, functional impairment or disease activity. In a multiple regression analysis, only recall bias made an independent contribution to PRISM. Conclusions: Illness self-schema appears to play a significant role in determining the way in which SLE patients complete the PRISM task. This is discussed in light of a schema enmeshment model recently proposed in the cognitive bias literature.