This article was originally published in March 2017. It has been revised to reflect more recent research.
The prevalence of autism in the United States has risen steadily since researchers first began tracking it in 2000. The rise has sparked fears of an autism ‘epidemic.’ But experts say the bulk of the increase stems from a growing awareness of the condition and changes to its diagnostic criteria.
Here’s how researchers track autism’s prevalence and explain its apparent rise.
How do clinicians diagnose autism?
There is no blood test, brain scan or any other objective test that can diagnose autism — although researchers are actively trying to develop such tests. Clinicians rely on observations of a person’s behavior to diagnose the condition.
In the U.S., the criteria for diagnosing autism are laid out in the Diagnostic and Statistical Manual of Mental Disorders (DSM). The criteria are problems with social communication and interactions, and restricted interests or repetitive behaviors. Both