Peripersonal Space Plasticity in Relation to Psychopathology and Anomalous Subjective Experiences in Individuals With Early-Onset and Adult-Onset Schizophrenia.

Introduction: Individuals with schizophrenia present anomalies in the extension and plasticity of the peripersonal space (PPS), the section of space surrounding the body, shaped through motor experiences. A weak multisensory integration in PPS would contribute to an impairment of self-embodiment processing, a core feature of the disorder linked to specific subjective experiences. In this exploratory study, we aimed at: (1) testing an association between PPS features, psychopathology, and subjective experiences in schizophrenia; (2) describing the PPS profile in individuals with early-onset schizophrenia.

Materials and methods: Twenty-seven individuals with schizophrenia underwent a task measuring the PPS size and boundaries demarcation before and after a motor training with a tool. The Positive And Negative Syndrome Scale (PANSS), the Examination of Anomalous Self Experience scale (EASE) and the Autism Rating Scale (ARS) were used to assess psychopathology. Subsequently, participants were divided into two subgroups, early and adult-onset schizophrenia. The two groups were compared in regard to their PPS and psychopathological profiles.

Results: PPS patterns were associated with psychopathology, particularly positively with PANSS negative scale score, and negatively with subjective experiences of existential reorientation (EASE Domain 5 scores) and of social encounters (ARS scores). Only PPS parameters and ARS scores differentiated between early and adult-onset participants.

Conclusions: Our results, although preliminary and exploratory, can suggest a link between PPS patterns, negative symptoms, and disturbances of the subjective experience, particularly in the intersubjective domain, in schizophrenia. Moreover, they seem to suggest that specific PPS profiles and schizophrenic autism traits could be markers of early-onset schizophrenia.