Relating latent factors of reasoning, affect, and cognition to the delusional experience.

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. The current study presents data on task-based reasoning biases and self-reported cognitive biases, as well as cognition and affect. Using these data, we aimed to understand mechanisms underlying facets of clinical delusional severity and broader unusual thought content. 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. 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. Affect was significantly associated with delusional preoccupation and distress. Belief updating was the primary factor associated with conviction. Cognitive biases related to the number of unusual beliefs endorsed, but no other aspects of severity. General cognitive ability was unrelated to all facets of delusional severity in our sample. Affective disturbances and belief updating map onto distinct aspects of clinical delusions in SSD; delusion severity is not robustly related to cognitive impairment. Reducing delusional conviction may require treatments focused on how new evidence is integrated into existing beliefs.