It is said that less than 1 percent of children have selective mutism.
According to a paper in Journal of the American Academy of Child and Adolescent Psychiatry, the prevalence of selective mutism is estimated about 0.7 percent.
Also in Japan, many psychologists have estimated and reported the prevalence.
Kawai (1994) gathered the Japanese literature in 1959-1980, and summarized that the prevalence of selective mutism is about 0.15-0.38 percent.
In more resent study, Muramoto (1983) sent questionnaires to public elementary schools and public junior high schools (except special schools) in Kamikawa district, norther Japan, and put the incidence at 0.027 percent in elementary schools and 0.041 percent in junior high schools.
Hasegawa and Kaneda (1996) also sent questionnaires to day-care centers and kindergartens in the City of Sizuoka, the center of Japan, and reported that the incidence of selective mutism was 0.1 percent.
As long as I know, all Japanese literature reported that there were more selectively mute girls than boys. That is common to the literature in other countries.
Looking back on my school days, I saw many reticent and shy children. But I didn't see mute and extremely shy children like me. I believed that there may have been no children like me in the world.
But other Japanese people said that there were at least one child with selective mutism in every school.
[Conclusion]
Selective mutism seems to be rare disorder also in Japan. Prevalence of selective mutism in Japan also may be less than 1 percent. But it may be not be as large as in the US. One common thing between the literature in Japan and other countries is that there are more selectively mute girls than boys.
Index of SM in Japan
