Supplementary Material for: The Autism Rating Scale for Schizophrenia – Revised English Version: An Instrument to Characterize Schizophrenia Spectrum Disorders Phenotype

Dis-sociality (DS) reflects the impairment of social experience in people with schizophrenia; it encompasses both negative features (disorder of attunement, inability to grasp the meaning of social contexts, the vanishing of social shared knowledge) and positive features (a peculiar set of values, ruminations not oriented to reality), reflecting the existential arrangement of people with schizophrenia. DS is grounded on the notion of schizophrenic autism as depicted by continental psychopathology. A rating scale has been developed, providing an experiential phenotype. Here we present the Autism Rating Scale for Schizophrenia – Revised English version (ARSS-Rev), developed on the Italian version of the scale. The scale is provided by a structured interview to facilitate the assessment of the phenomena investigated here. ARSS-Rev is composed of 16 distinctive items grouped into 6 categories: hypo-attunement, invasiveness, emotional flooding, algorithmic conception of sociality, antithetical attitude toward sociality, and idionomia. For each item and category, an accurate description is provided. Different intensities of phenomena are assessed through a Likert scale by rating each item according to its quantitative features (frequency, intensity, impairment, and need for coping). The ARSS-Rev has been able to discriminate patients with remitted schizophrenia from euthymic patients with psychotic bipolar disorder. This instrument may be useful in clinical/research settings to demarcate the boundaries of schizophrenia spectrum disorders from affective psychoses.