Resolving the Delusion Paradox
Schizophrenia Bulletin July 21, 2023 Predrag Petrovic, Philipp Sterzer 42 citations
Delusions in psychotic disorders are hard to reconcile with the predictive processing (PP) framework, which suggests psychosis involves reduced weighting of prior beliefs relative to sensory data—yet delusions are highly resistant to change. This paradox can be resolved by a hierarchical PP model: reduced weighting of low-level priors may be compensated by increased influence of higher-order beliefs, including delusional beliefs, which then shape perception and resist contradictory evidence. A review of experimental evidence supports decreased weighting of low-level priors and increased weighting of high-level priors in both delusional and delusion-prone individuals. The prefrontal cortex is highlighted as a neural basis for this increased weighting of high-level priors, with clinical implications discussed.