Prevalence of Autism/ASD Among Preschool and School-age Children in Norway

In recent years, there has been a considerable rise in prevalence rates for autism/autism spectrum disorders (ASD) around the globe. Understanding the patterns of prevalence is essential for policy development at national and local levels that effectively plans for medical, psychological, behavior analytical, and educational interventions. This study presents new data on the prevalence of ASD among preschool and school-age children (ages 1–16 years) in Norway. Based on the International Classification of Diseases (ICD-10) criteria for diagnosis, the rate of ASD increased from 2014 to 2016. The study found a much higher increase in prevalence rate among preschool-age (1–5 years) children than school-age (6–16 years) children over the same 2-year period. At the same time, however, the rate of ASD among school-age children (6–16) compared with that among preschool children (1–5) is higher in 2014 and 2016, indicating a school-age effect. The results also indicate a shifting pattern of gender difference in diagnosed preschool-age children. The male-to-female ratio receiving an ASD diagnosis has increased from 4.46:1 in 2014 to 4.57:1 in 2016, suggesting that the gender gap may be slightly widening for preschool children. For school-age children, the gender gap (male-to-female ratio) is slightly narrowing, moving from 3.53:1 in 2014 to 3.46:1 in 2016. While these changes may not seem significant, the implications of the full findings are discussed.