Altered interoceptive-exteroceptive profile in Generalized Anxiety Disorder: Evidence from bayesian psychophysics and metacognitive modeling.

Generalized Anxiety Disorder (GAD) is believed to involve impaired processing of external information and excessive focus on internal bodily signals. However, comparative evidence on exteroceptive and interoceptive performance within a common experimental framework remains limited. In the present study, individuals with GAD (n = 31) and healthy controls (HC; n = 31) completed a heart rate discrimination (HRD) task, combined with Bayesian psychophysical modeling and signal detection theory-based metacognitive indices. At the first-order level, we estimated an HRD threshold parameter (α), indexing systematic tendency in cardiac judgments, and a precision parameter (β; lower β indicates greater precision), indexing the sharpness or uncertainty of those judgments. At the second-order level, we estimated metacognitive sensitivity (meta-d'), reflecting how well confidence tracked first-order task performance. We also included exploratory self-report measures of bodily awareness and bodily appraisal using the Body Awareness Questionnaire and the Body Sensations Interpretation Questionnaire. In the HC group, participants showed a relative exteroceptive advantage within the HRD framework, reflected in lower β and higher meta-d' in the exteroceptive condition than in the interoceptive condition. By contrast, this within-group exteroceptive advantage was not observed in GAD. Relative to HC participants, individuals with GAD showed greater precision in HRD-based cardiac judgments (lower β) and reduced exteroceptive metacognitive sensitivity (lower meta-d'), whereas no group differences emerged for α or the exploratory self-report measures. Taken together, these findings suggest an altered interoceptive-exteroceptive performance profile in GAD, characterized by greater precision in cardiac judgments alongside weaker exteroceptive metacognitive monitoring. These results may help refine theoretical accounts of internal-external information processing in anxiety and inform future computational approaches to assessment in GAD.