Abstract: Mental disorders have become both a severe and costly global public health issue and prominent societal challenge. Mental illnesses not only contribute to a substantial disease burden but also represent a major cause of disability worldwide. Among mental disorders, schizophrenia is a severe psychotic illness characterized by high risk, high disease burden, significant functional impairment, and chronic progression. Furthermore, the disorder is closely associated with agency disturbances. However, the alterations in agency and clinical correlation with symptoms remain incompletely understood. We investigated the manifestations of abnormal agency in schizophrenia and clarified the relationship between abnormalities and psychiatric symptoms. Accordingly, we further explored the neural mechanisms underlying the aberrant agency in schizophrenia at an electrophysiological level.
Experiment 1 was a behavioral study in which a 2 (type: schizophrenia patients, healthy controls) × 2 (task: baseline, action) × 5 (interval: 100 ms, 300 ms, 500 ms, 700 ms, 900 ms) mixed design was used to investigate the manifestations of abnormal agency. We conducted correlation analyses between indicators of the agency and psychotic symptoms in schizophrenia. Experiment 2 was an ERP study in which the neural mechanisms underlying agency deficits were clarified by examining motor intention and sensory prediction.
Behaviorally, compared to healthy controls, schizophrenia exhibited significantly lower agency ratings, prolonged time interval estimations in action task, and attenuated intentional binding. Critically, the degree of agency disturbances positively correlated with positive symptoms, thereby suggesting that patients display a weakened agency, and pathologically weakened agency is closely linked to positive symptoms. In neural activity, in the motor intention stage, patients with schizophrenia exhibited neural impairment, specifically manifested as a significantly reduced amplitude gain of the readiness potential in the action task compared with healthy controls, despite the presence of the readiness potential. In the sensory prediction, patients exhibited relatively preserved predictive inhibitory processing of self-generated sensory stimuli, as evidenced by the lack of significant group differences in N1 and P2 suppression. Therefore, the attenuated sense of agency observed in schizophrenia may primarily stem from neural deficits in the motor preparation.
This study demonstrates a significantly weakened agency in schizophrenia, which was positively linked to positive symptoms. In addition, this weakened agency may be associated with impaired motor intention. Future intervention research should prioritize motor intention-related regions as potential targets to improve the sense of agency in schizophrenia.

Key words: schizophrenia, sense of agency, motor intention, sensory prediction