TOKYO -- Around one in 30 children aged 5 were found to have autism spectrum disorder (ASD) in a study conducted in Aomori Prefecture in northern Japan.
The discovery was made by a research team led by Manabu Saito, an associate professor in child and adolescent psychiatry at Hirosaki University, and was published in a British academic journal. It is the first time that the estimated rate of the prevalence of ASD among children under primary school age has been revealed in the country.
The study was carried out in the city of Hirosaki, Aomori Prefecture, between 2013 and 2016 on a total of 5,016 children who had taken medical checkups for 5-year-olds. The team distributed questionnaires to guardians and caregivers asking about the extent of their child's development, and obtained responses from 3,954 people. Among them, the team then used American Psychiatric Association guidelines for assessing developmental issues to examine a total of 559 children who had either shown an inclination toward developmental disabilities including ASD, or whose parents requested an examination.
As a result, 87 children were diagnosed with ASD. When considering the number of children who, despite their guardians and caregivers not answering the questionnaire, showed potential signs of developmental disabilities during medical checkups, it was estimated that 3.22% of 5-year-old children had ASD. There were no distinct differences in the percentages of ASD diagnoses per year. The team said that the percentage of 5-year-olds with ASD nationwide is thought to be similar in number.
Of the 87 children diagnosed with ASD, the guardians of 28 children had never been informed of any delays in their development until the age of 5, and had not received any systematic support. In addition, 88.5%, or 77 children, had one or more developmental disabilities besides ASD, including developmental coordination disorder (63.2%), attention deficit hyperactivity disorder (50.6%), and intellectual development disorder (36.8%).
Research team leader and associate professor Saito commented, "The unique characteristics of these children should be acknowledged and thorough support should be extended before they enter elementary school."
(Japanese original by Ayumu Iwasaki, Science & Environment News Department)