Signs & Symptoms

Autistic infants who have extreme responses to sights, sounds or textures tend to harm themselves as toddlers.

Most 4-year-old autistic children cannot string more than two words together.

Depression may influence how people with autism perform on tests of social function.

Restricted and repetitive behaviors decrease significantly in about 75 percent of autistic children from age 3 to 11.

Autistic children are more likely to have gastrointestinal problems than typical children are, but no more so than children with other brain conditions.

Two drugs that alter the activity of the hormone vasopressin seem to improve social communication in autistic people, but some experts question the findings.

One of the leading theories of autism posits that girls and women are biologically protected from the condition.

The ‘extreme male brain’ theory suggests that autism is an exaggeration of systematic sex differences in ways of thinking.

Serotonin, the brain chemical best known for its link to depression, may also be involved in autism.

Some autistic children’s communication and motor skills begin to decelerate between 9 and 18 months — years before the average age of diagnosis.