Prevalence of autism in U.S. children aged 8 years in selected states 2020
Autism spectrum disorder in children
Among eleven U.S. states with areas that were monitored for autism spectrum disorder in 2020, California had the highest prevalence rates of autism spectrum disorder (ASD) among children aged eight years. In 2020, California’s prevalence rate was estimated to be 44.9 cases per 1,000 children while the rate was about 23 cases per 1,000 children in Maryland. ASD is more common among male than female children, with an estimated 69.4 male cases per 1,000 children and 19.1 female cases per 1,000 children in California in 2020.
Limitations in a child with autism can vary between individuals and develop over time. In California, the median age of diagnosis among children with an ASD diagnosis with an IQ greater than 70 was 35.5 months of age, in comparison to 39 months for children with an ASD diagnosis and an IQ less than or equal to 70, indicating a co-occurring intellectual disability.
Prevalence of ASD has increased significantly since the late 1960s by about 20 to 30 times. Many studies suggest that this is due to improved awareness and recognition as well as diagnostic capabilities. For those living with autism, lifetime costs may total up to 2.68 million U.S. dollars. Autism is likely caused by a combination of genetics and environmental factors, where people with ASD may have abnormal levels of brain serotonin which could disrupt early brain development.