Everything is connected: Inference and attractors in delusions

SCHIZOPHRENIA RESEARCH

卷:245

Article

Adams, Rick A.^1,2  Vincent, Peter³  Benrimoh, David⁴  Friston, Karl J.⁵  Parr, Thomas⁵ 

[1] UCL, Ctr Med Image Comp, Dept Comp Sci, 90 High Holborn, London WC1V 6LJ, England

[2] UCL, Max Planck Ctr Computat Psychiat & Ageing Res, Russell Sq House,10-12 Russell Sq, London WC1B 5EH, England

[3] UCL, Sainsbury Wellcome Ctr, 25 Howland St, London W1T 4JG, England

[4] McGill Univ, Dept Psychiat, Montreal, PQ H3G 1A4, Canada

[5] UCL, Wellcome Ctr Human Neuroimaging, 12 Queen Sq, London WC1N 3AR, England

关键词: Delusions;    Active inference;    Paranoia;    Bayesian;    Computational psychiatry;    Choice-induced preference change;   

DOI  :  10.1016/j.schres.2021.07.032

来源: Elsevier

【 摘 要 】

Delusions are, by popular definition, false beliefs that are held with certainty and resistant to contradictory evidence. They seem at odds with the notion that the brain at least approximates Bayesian inference. This is especially the case in schizophrenia, a disorder thought to relate to decreased - rather than increased - certainty in the brain's model of the world. We use an active inference Markov decision process model (a Bayes-optimal decision-making agent) to perform a simple task involving social and non-social inferences. We show that even moderate changes in some model parameters - decreasing confidence in sensory input and increasing confidence in states implied by its own (especially habitual) actions - can lead to delusions as defined above. Incorporating affect in the model increases delusions, specifically in the social domain. The model also reproduces some classic psychological effects, including choice-induced preference change, and an optimism bias in inferences about oneself. A key observation is that no change in a single parameter is both necessary and sufficient for delusions; rather, delusions arise due to conditional dependencies that create 'basins of attraction' which trap Bayesian beliefs. Simulating the effects of antidopaminergic antipsychotics - by reducing the model's confidence in its actions - demonstrates that the model can escape from these attractors, through this synthetic pharmacotherapy.

【 授权许可】

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