Self-Structure in Persecutory Delusions

There is currently limited research examining self-structure in clinical groups and no current data on the extent to which self-structure is amendable to change following psychological therapy. We address this important gap by examining self-structure in individuals with persecutory delusions using the card sort task, an established paradigm measuring key self-structure indices, including the degree to which self-structure is compartmentalized (characterized by primarily positive or negative attributes, as opposed to a mix of both), and the proportion and importance of negative attributes. In Study 1, individuals with a schizophrenia spectrum diagnosis with current persecutory delusions (clinical group, n = 27) and a healthy control group (n = 47) were compared on self-structure indices. In Study 2 (n = 27), the clinical group also completed the card sort task before and after randomization to either a 12-week mindfulness-based psychological therapy or treatment-as-usual control. In Study 1, self-structure differed significantly between the clinical and control groups. The clinical group had a greater proportion of negative attributes, assigned more importance to negative self-aspects, and had more compartmentalized self-structures compared with controls. In Study 2 there were no associations between delusion severity and self-structure. Large effect sizes for reductions in compartmentalization and proportion of negative attributes across self-aspects were found following mindfulness therapy. The findings highlight key differences in self-structure between individuals with persecutory delusions and healthy controls, and suggest that it might be possible to change self-structure following psychological therapy. These data support the central role of the self in theoretical models of paranoid thinking.