Gone fishin'… for distinct patterns of belief-updating in late-life worry and rumination.

Introduction: Worry and rumination are two common forms of repetitive negative thinking encountered as core symptoms of anxiety and depression. They are difficult to treat and increase the risk of relapse for remitted depressive and anxiety disorders, especially in late-life. We propose that dysfunctional belief-updating is a fundamental cognitive mechanism underlying repetitive negative thinking and use a Bayesian model to test whether distinct components of belief updating are differentially associated with worry and rumination. Methods: We recruited 83 older participants (age≥50) dimensionally for worry and rumination to perform a belief-updating task and undergo neuropsychological testing. We extracted three parameters from a Bayesian model of belief-updating: performance compared to the Bayesian optimal model, emphasis on initial information (prior weight), and relative weighting of new evidence compared to current beliefs (update strength). These parameters were tested for associations with worry and rumination severity, and four neuropsychological domains were tested as moderators (attention, visuospatial, working memory maintenance, and executive function). Results: Worry severity was uniquely associated with lower prior weight, while rumination was associated with low update strength. Neither worry nor rumination were associated with performance. None of the neuropsychological domains moderated these relationships. Conclusion: Worry and rumination are associated with unique alterations in belief-updating but not overall performance. Low prior weight in worry may inflate perceived uncertainty, while low update strength in rumination-specifically reflective pondering-is consistent with slower incorporation of new information. Both biases may contribute to the distinct phenomenological profiles of worry and rumination and inform specific therapeutic targets for these symptoms.