Predictive role of exteroceptive and interoceptive bodily dimensions to schizotypal personality traits.

The phenomenological approach to schizophrenia emphasizes the role of bodily experiences in the onset and manifestation of positive, negative and disorganized psychotic symptoms. According to the dimensional approach to psychosis, there exists a continuum ranging from individuals with low levels of schizotypy to diagnosed schizophrenia patients, with schizotypy encompassing positive-like, negative-like, and disorganized-like symptoms of schizophrenia. Empirical evidence suggests that along this continuum, both exteroceptive (external sensory) and interoceptive (internal bodily) dimensions might be distorted. Understanding the contribution of these bodily dimensions in the manifestation of psychotic symptoms, even in schizotypy, might help target early interventions for individuals at risk of developing psychotic disorders. This study investigated the potential contribution of exteroceptive and interoceptive bodily dimensions to schizotypal personality traits, such as cognitive-perceptual traits (positive-like symptoms), interpersonal traits (negative-like symptoms), and disorganization traits (disorganized-like symptoms). Partial Least Squares Regression was used to integrate several bodily dimensions to understand their impact on schizotypy, revealing specific and non-specific contributions of exteroceptive and interoceptive dimensions to different traits. In particular, exteroceptive bodily dimensions generally predicted all schizotypal traits, with specific associations to positive-like symptoms, while interoceptive dimensions mostly predicted interpersonal-like and disorganized-like symptoms. These results suggest a difference in how exteroceptive and interoceptive bodily dimensions contribute to the three schizotypal traits. This highlights specific aspects of interoceptive and exteroceptive body representations that could serve as targets for early intervention. Particularly, interoception emerges as a potential prodromal marker, suggesting that early intervention in this area could be crucial.