Support for Predictive Processing Assumptions on Health Anxiety: Imprecise Expectations on the Origin of Somatic...

In pathologic health anxiety (pHA), a more liberal interoceptive response bias and health-threat related biases are observed. In predictive processing terms, this could be translated into a precise prior on high somatic symptom probability (symptom-prior) and an imprecise prior on one's current (and future) health state (hidden-state-prior).

In an online experiment, we used an adapted version of the affect and symptom paradigm (ASP), previously shown to sufficiently elicit somatic symptoms. N = 261 participants (age: M = 27.79, SD = 9.61; sex: 77.8% females, 21.5% males, 0.8% divers) were randomly assigned to 4 conditions, manipulating priors on somatic symptom probability (symptom-prior: precise and high probability vs precise and low probability) and origins of somatic symptoms (hidden-state-prior: imprecise vs precise and nonillness).

We did not observe any significant effects of symptom-prior manipulation on symptom report ( p = .27). Inducing an imprecise prior on the origin of somatic symptoms (imprecise hidden-state-prior), though, was significantly associated with higher health anxiety after negative (compared with neutral) pictures in people with higher preexisting health anxiety [ b =0.113, SE = 0.045, 95% BCa CI (0.025, 0.201)]. This effect was not attributable to a simultaneous change in valence or arousal ( pval = .73; paro = .56).

The findings suggest a possible central role of imprecise priors, especially on one's health state, in pHA. Further evidence in clinical samples is needed.