How mood shapes belief updating bias in depression.

Major depressive disorder (MDD) is characterized by mood-congruent beliefs, such as devaluation, unworthiness, helplessness, pessimism, or guilt. These depressive beliefs could cause and maintain emotional and behavioral disturbances, playing a central role in MDD prognosis. Drawing on studies exploring how mood affects information processing, we propose a mechanistic theory of belief updating in depression. First, we show how depressive beliefs are formed in environments where negative stimuli are weighted more heavily. Second, we demonstrate how depressed individuals often hold rigid negative metacognitive priors that inhibit belief updating. Third, we clarify how negative beliefs can be generated internally through repetitive, self-focused cognitive patterns. Finally, we critically examine the limitations of current experimental paradigms used to assess belief updating, highlighting methodological constraints and potential confounds. Based on these insights, we outline future research directions to refine experimental designs and improve our understanding of mood-congruent belief updating in depression.