A computational analysis of abnormal belief-updating processes and their association with psychotic experiences and childhood trauma in a UK birth cohort

Background Psychotic experiences emerge from abnormalities in perception and belief formation, and occur more commonly in those experiencing childhood trauma. Yet, which precise aspects of belief formation are atypical in psychosis is not well understood. We used a computational modelling approach to characterise belief-updating in young adults in the general population, examine their relationship with psychotic outcomes and trauma, and the extent to which they mediate the trauma-psychosis relationship.MethodsWe used data from 3,360 individuals from the Avon Longitudinal Study of Parents and Children birth cohort who completed assessments for psychotic outcomes, depression, anxiety, and two belief-updating tasks at age 24, and had data available on traumatic events assessed from birth to late adolescence. Unadjusted and adjusted regression and counterfactual mediation methods were used for the analyses.ResultsBasic behavioural measures of belief-updating (‘draws to decision’ and ‘disconfirmatory updating’) were not associated with psychotic experiences. However, computational modelling revealed an association between increased decision noise with both psychotic experiences and trauma exposure, although ConclusionsThese findings challenge the hypothesis that atypical belief-updating mechanisms (as indexed by the computational models and behavioural measures we employed) underlie the development of psychotic phenomena.