Examining reasoning bias, affective, and cognitive structures in relation to the delusional experience

Background: Reasoning biases play a crucial role in the formation and maintenance of delusions. In psychosis, it is unclear whether these biases cluster onto similar underlying factors or represent independent constructs. Here, we capture both task-based reasoning biases and self-reported cognitive biases, as well as cognition and affect to understand mechanisms underlying metrics of clinical delusional severity and broader unusual thought content. Methods: Participants with schizophrenia-spectrum disorders (SSD; N=75) were enrolled following hospitalization for an acute psychotic episode. Non-clinical comparison participants (NCC; N=70) were recruited for comparison of affect, cognition, and reasoning biases. Exploratory factor analysis and multivariable linear regressions were performed in the SSD group only. Core clinical delusions and broader unusual thought content, alongside preoccupation, conviction, and distress were used as outcome measures. Results: SSD participants had more severe reasoning biases, cognitive deficits, and negative affect than NCC. In SSD, factor analysis revealed four latent constructs representing belief updating, cognitive biases, affective disturbances, and general cognitive ability. Affective disturbances were significantly associated with delusional preoccupation and distress. Belief updating was the only factor associated with conviction. Cognitive biases related only to the number of unusual beliefs endorsed, but no other aspects of severity. General cognitive ability was unrelated to all facets of delusional severity. Conclusion: Affective disturbances and belief updating map onto distinct aspects of clinical delusions in SSD: distress/preoccupation and conviction, respectively. Delusion severity is broadly unrelated to cognitive impairment. Reducing delusional conviction may require treatments focused on how new evidence is integrated into existing beliefs.