Epidemiology of ASD in Preschool-age Children in Japan

In recent years, it has been reported that the prevalence of autism spectrum disorder (ASD) is increasing, but there are few research reports in Asia equivalent to those in Europe and the United States. Since large-scale epidemiological studies of neurodevelopmental disorders (NDDs) have not been conducted in Japan, the delay in early detection is conspicuous compared to other countries. Therefore, we started epidemiological studies in a medium-sized city (Hirosaki City) in northern Japan from 2013 to elucidate the prevalence of ASD and have been conducting a 9-year community cohort survey. In 2020, we published an adjusted prevalence of ASD of 3.2% at the age of 5 years, no change in 4-year incidence, and comorbidity of ASD. Since then, we have focused on sleep problems at the age of 5 years and have been studying the estimation of the prevalence of sleep disorders and the relationship with neurological development disorders. In this chapter, in addition to our research results since 2013, we will introduce the screening and support system in the community in Japan.