Abstract
Selective mutism（SM）is identified as an anxiety disorder in DSM-5（Diagnostic and Statistical Manual of Mental Disorders, 5th ed.）．According to previous studies, SM appears to represent an underlying heterogenic group of disorders. This study aimed to classify children with SM based on their background factors of mutism. The study participants included 22 children with SM aged 6-12 years. A cluster analysis was performed using scores of background factors, autism traits（SCQ）， communication（CCC-2），and anxiety（SCAS）．The results indicated that participants were classified into three groups. In the group with relatively high communicative competence（n=11），the participants showed separation anxiety and social anxiety, but had no noticeable comorbidities. Poor communication performance was confirmed in the groups with relatively high autism traits score（n=8）and higher anxiety（n=3）．
