Reduced sensory attenuation is related to aberrant interoceptive influences on intentional binding in schizophrenia

Schizophrenia (SZ) is characterized by abnormalities in self-representation, including an aberrant sense of agency (SoA). Experimentally observed abnormalities in force matching and intentional binding tasks suggest that the SoA in SZ is compromised at the implicit level. However, these task effects have been reported independently, leading to inconsistencies that complicate the understanding of SZ pathophysiology.

Thirty-three patients with SZ and 37 nonclinical (healthy) controls (HCs) performed force matching and intentional binding tasks. The former task assessed sensory attenuation, while the latter evaluated an intentional binding effect, both measuring implicit levels of SoA. We previously observed that the cardiac phase (systole vs diastole) influences intentional binding. Therefore, we investigated the relationship between sensory attenuation and intentional binding, including this "cardiac effect," which refers to the influence of cardiac interoceptive signals.

In SZ, significantly reduced sensory attenuation, a greater but nonsignificant intentional binding effect, and a significant opposite cardiac effect were observed compared with HCs. Sensory attenuation and intentional binding were significantly and positively correlated in the SZ group but not in the HC group. Across all participants, sensory attenuation correlated with the cardiac effect on intentional binding. This effect remained significant in the HC group but not in the SZ group.

Group differences and task associations suggest shared mechanisms and pathophysiology in SZ, potentially involving impaired predictive processes and the failure of sensory attenuation. The cardiac effect may be explained by interoceptive sensory attenuation, and its failure could lead to a disturbed SoA in patients with SZ.