Association between Delusions, Belief Flexibility, and Cognitive Control in Schizophrenia - A 6-Month Repeated-Measures Study.

Background: There is robust evidence that belief inflexibility is critical to the maintenance of delusion conviction. While cognitive control abilities (inhibitory control, mental set shifting, and working memory updating) are instrumental to information processing in general, and there is evidence that these abilities are disrupted in patients with schizophrenia, the extent to which these processes are associated with delusions as well as belief flexibility is less studied. Method: Adult patients with schizophrenia spectrum disorders and active delusions (N = 66) completed three cognitive control tasks (negative priming, alternating runs, and n-back) at baseline and 6 months after. Cross-sectional and repeated measures associations between cognitive control abilities, belief flexibility, and delusions were evaluated. Results: At baseline, the reaction time switch cost of mental set shifting was positively correlated with level of delusion severity. Over 6 months, an increase in working updating ability was associated with a decrease in delusion conviction, and an increase in negative priming effect was associated with an increase in belief flexibility. There was no evidence for belief flexibility as a mediator between cognitive control and delusions, either cross-sectionally or over time. Discussion: This is the first study reporting the association between three cognitive control abilities, belief flexibility, and delusions using a single-symptom approach (involving patients with psychotic delusions). If replicated, these findings may attest to the potential of further ameliorating drug-resistant delusions through targeting cognitive control as well as belief flexibility.