By Nancy Lapid
Autism diagnoses in the United States have increased significantly since 2000, intensifying public concern over what might contribute to its prevalence. There are no objective tools for diagnosing autism such as blood tests or brain scans. Instead, diagnoses are made based on observations and interviews.
By 2020, the U.S. autism rate in 8-year-olds was 1 in 36, or 2.77%, up from 2.27% in 2018 and 0.66% in 2000, according to the U.S. Centers for Disease Control and Prevention. A 2021 study from England put the rate in children there at 1.76%, up from 1.57% in 2009.
The World Health Organization estimates the worldwide prevalence in children at 1%, up from 0.62% in 2012, with the caveat that many countries lack the resources to identify cases and report them.
The causes of autism are unclear. There is widespread speculation among scientists that its neurological characteristics may develop in utero, when the fetal brain is being wired. Studies have linked autism to maternal factors in pregnancy, and some research suggests a link to birth complications and timing.
A growing area of research focuses on epigenetics – the interactions between genetic and environmental factors. Gene variations in some people with autism strengthen the evidence for a genetic component. Among the genetic disorders linked with higher risks for autism are Fragile X syndrome, tuberous sclerosis complex, Phelan-McDermid syndrome, and Prader-Willi syndrome.
Other potential risk factors may include a sibling with autism, the age of parents when conceiving children, very low birth weight, jaundice as a newborn, complications in utero or during birth, having an unhealthy assortment of organisms living in the intestines, and immune system disorders.
Researchers attribute the rise in autism diagnoses to more widespread screening and the inclusion of a wider range of behaviors to describe the condition.
An October 2024 study of U.S. insurance claims data found the largest increases in diagnoses were in groups with low screening rates in the past, including young adults, females, and children from some racial or ethnic minority groups.
There are no treatments or cures for autism, nor can it be reversed. However, experts agree that early diagnosis is crucial. Intervention with supportive measures – ideally before age three – is critical for improving cognitive, social and communication skills.
Such measures can include speech therapy, occupational therapy, social skills training, sensory integration therapy, visual aids, structured routines, individualized education plans, family therapy, and providing a calm and predictable environment. – Reuters