Normative values and diagnostic optimisation of three social cognition measures for autism and schizophrenia diagnosis in a healthy adolescent and adult sample

Awareness of the importance of assessing social cognition skills under conditions showing atypical social behaviours has increased over the years. However, the evaluation of the psychometric properties of the measures and the availability of normative values for the clinical context are still limited. This study aims to revise, provide normative values, and evaluate the clinical validity of the Italian version of three social cognition measures: Advanced Theory of Mind (A-ToM) task, the Emotion Attribution Task (EAT), and the Social Situation Task (SST). Measures were administered to 580 adolescents and adult healthy controls (age range 14-50). We performed differential item functioning and Rasch analysis to revise each task, so normative data of the revised measures were calculated. Moreover, the revised measures were administered to 38 individuals with autism spectrum disorder (ASD) and 35 individuals with schizophrenia spectrum disorders (SSD): ASD and SSD were matched by age, gender, and IQ with a control sample to evaluate clinical validity. ROC analysis showed that the SST is the best measure differentiating between healthy and clinical groups, compared to the A-ToM (AUC(ASD) = 0.70; AUC(SSD) = 0.65) and EAT (AUC(ASD) = 0.67; AUC(SSD) = 0.50), which showed poorer performance. For SSD diagnosis, two SST subscales (Violation and Gravity score) indicated the best accuracy (AUCs of 0.88 and 0.84, respectively); for the ASD diagnosis, we propose a combined score between the SST subscale and A-ToM (AUC = 0.86). The results suggest that the proposed measures can be used to support the diagnostic process and clinical practice.