Tehran University of Medical Sciences Iranian Journal of Psychiatry 1735-4587 19 2 2024 03 16 218 225 Najmeh Tavakolian Research Center for Cognitive and Behavioral Sciences, Roozbeh Psychiatry Hospital, Tehran University of Medical Sciences, Tehran, Iran. Zahra Shahrivar Department of Psychiatry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Javad MahmoudiGharaie Department of Psychiatry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Sara Hojatitabar Department of Psychiatry, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran. Fatemeh Mehrzad Department of Psychiatry, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran. Mehdi Tehrani-Doost Research Center for Cognitive and Behavioral Sciences, Roozbeh Psychiatry Hospital, Tehran University of Medical Sciences, Tehran, Iran. 2023 02 26 2023 11 13 Objective: Early detection of autism spectrum disorder (ASD) can lead to earlier intervention and greater improvement of children’s quality of life and performance; hence, the use of screening tools is essential to facilitate the diagnosis process. The aim of the present study was to determine the clinical and differential validity of Social Responsiveness Scale-Second Edition (SRS-2) and Social Communication Questionnaire (SCQ)in a group of children and adolescents with autism spectrum disorder compared to a normal developmental group. Method: The study was conducted in Roozbeh Hospital involving 52 children with ASD and 53 typically developing (TD) children, aged between 4-12 years. Their parents completed the SRS-2 and SCQ. These children were also interviewed using the Childhood Autism Rating Scale, 2nd Edition (CARS-2) and Asperger Syndrome Diagnostic Scale (ASDS). After completion, the results were analyzed using the SPSS Version 18 software and a significant level of 0.05. Results: The average age of children in the autism group was 7.5 ± 2.7 years, while in the typically developing (TD) children group, it was 7.7 ± 2.3 years (P = 0.656). A positive correlation coefficient was observed between the CARS questionnaire score, the SRS questionnaire score, the SCQ questionnaire score, and the ASDS ‏(P < 0.01). In the SRS questionnaire, the area under the ROC curve was 0.976, and in the SCQ questionnaire it was 0.953, both of which had a good and significant diagnostic value (P < 0.001). A sensitivity of 0.942 and specificity of 0.811 for the cut-off point of 62.5 were obtained in the SRS questionnaire. Additionally, a sensitivity of 0.865 and specificity of 0.925 for the cut-off point of 15.5 were achieved in the SCQ questionnaire. Conclusion: The SRS-2 and the SCQ are sensitive and specific tools for identifying and discriminating children with autism spectrum disorder. https://ijps.tums.ac.ir/index.php/ijps/article/view/3518