Signs and symptoms of autism spectrum disorder include difficulty with eye contact, facial expressions, body posture and other ways of communicating without words, and a lack of interest in being a part of others' achievements, interests and hobbies, according to WebMD. People with autism spectrum disorder may lack empathy, and they may not be able to understand when someone is feeling a strong emotion, such as grief.
People with autism may have trouble understanding when a person is being humorous, states WebMD. It is common for people with autism to insist on following a particular routine. Stereotyped behaviors, such as hand flapping or body rocking, are symptoms of autism spectrum disorder.
Children with autism spectrum disorder may not be willing to befriend other children of the same age, notes WebMD. As many as 40 percent of people with autism do not communicate verbally, and it is common to struggle with starting or maintaining a conversation. Echolalia is a symptom of autism spectrum disorder, which is when someone repeats a phrase over and over.
Symptoms of autism spectrum disorder are usually recognized within a person's first three years, according to WebMD. While the disorder does exist during infancy, it is usually difficult to detect initially. The severity of core autism spectrum disorder symptoms varies widely among different people.