Abstract
Discriminating between social communication disorder (SCD) and autism spectrum disorder (ASD) is essential because both show difficulties in social use of verbal and nonverbal communication. Unfortunately, there is a lack of useful auxiliary test findings. We investigated some auxiliary tests useful for differentiating SCD from ASD. The Social Responsiveness Scale, Second Edition (SRS-2), and the Metaphor and Sarcasm Scenario Test (MSST) were administered to 5 subjects in the SCD group and 25 subjects in the ASD group. T-scores of the SRS-2 on the DSM-5 compatible scales (1) Social Communication and Interaction (SCI) and (2) Restricted Interests and Repetitive Behavior (RRB) were in the clinical range in the ASD group; in the SCD group, SCI was in the clinical range and RRB was normal. In the MSST, although there was no difference in the percentage of correct answers for metaphor sentences between the two groups, the percentage of correct answers for sarcasm sentences was extremely poor in the SCD group. The combination of SRS-2 and MSST revealed clinical differences between SCD and ASD. Although there is some discussion about the differences between SCD and ASD, our results suggest that they may be different disease concepts.
