Conditioned hallucinations and prior hyper-precision are state-sensitive markers of hallucination susceptibility

Recent advances in computational psychiatry have identified latent cognitive and perceptual states that predispose to psychotic symptoms. Behavioral data fit to Bayesian models have demonstrated an over-reliance on priors during perception in select samples of individuals with hallucinations. However, the clinical utility of this observation depends on whether it reflects static symptom risk or current symptom state. To determine whether task performance and estimated prior weighting related to specific elements of symptom expression, a large, heterogeneous, and deeply-phenotyped sample of hallucinators (N = 249) and non-hallucinators (N=209) performed the Conditioned Hallucination (CH) task. CH rates were sensitive to hallucination state, correlating with hallucination severity measures over the two days leading up to task completion and driven by heightened reliance on past experiences (priors). To further test this relationship, a subset of AH+ participants (N = 40) performed a repeated-measures version of the CH task. Changes in both CH frequency and relative prior precision varied with changes in AH frequency on follow-up. These results support the use of CH rate and prior hyper-precision as state markers of hallucination status, potentially useful in tracking disease development and treatment response.