BACKGROUND:

An epidemiological survey of childhood autism as defined in ICD-10 Research Criteria was conducted in the northern part of Yokohama, Japan.

METHOD:

The routine health checkup for 18-month-old children served as the initial mass-screening, and all facilities which provide child care services function to detect all cases with childhood autism and refer them to the Yokohama Rehabilitation Centre.

RESULTS:

Cumulative incidence of childhood autism up to 5 years of age among the birth cohort of 1988, and prevalence on 1 January 1994, among residents born in 1988 were estimated

RESULTS:

Cumulative incidence and prevalence were 16.2 per 10,000 and 21.1 per 10,000, respectively. Children with high-functioning autism who had IQs of 70 and over constituted approximately half of all the children with childhood autism. CONCLUSION. It was confirmed through better detection of high-functioning cases that childhood autism in Japan is more common than formerly estimated.