Enrollment Rate of Children with Selective Mutism in Kindergarten, Elementary School, and Lower Secondary School in Japan

Several studies have been conducted on the prevalence of selective mutism. However, the subjects and methods differ between these studies, and no unified perspective has been achieved. The purpose of this study was to conduct a systematic investigation by school type and grade level of children with selective mutism enrolled in kindergarten, elementary school, and lower secondary school in Japan and to evaluate the prevalence of selective mutism. The overall enrollment rate for children with selective mutism, in a total of 73 public kindergartens and elementary and lower secondary schools was found to be 0.21%, with more female than male students (male-to-female ratio=1 : 2.1). The enrollment rate by school type was the highest for kindergarten (0.66%) and slightly decreased for the higher stages of education. The percentage of schools where any children with selective mutism were enrolled (called the school enrollment rate) was 39.7% for all schools and gradually increased from kindergarten to lower secondary school (at 46.7%). In this study, the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition diagnostic criteria for selective mutism were employed, and schoolteachers determined selective mutism based on the criteria. The school enrollment rate obtained in this study supports the results of other studies and provides new insights into selective mutism. The limitations of this study include an insufficient number of samples and a failure to ensure adequate interpretive skill on the part of the respondents.