Signs and symptoms of autism

Autism is relatively common, and there are various signs and symptoms of autism that can lead people to wonder if they or someone close to them has the disorder.

Recognizing the signs of autism can make it easier to decide if it's time to see a healthcare provider for an evaluation.

Autism is one of many conditions grouped under the term autism spectrum disorder, or ASD. About 1 in 54 children in the U.S. have ASD. It is marked by the following three main characteristics, although there may be more features:

• Difficulty with communication and social interactions with other people
• Limited interests and repetitive behaviors
• Symptoms that interfere with the person's ability to function in school, work and society in general

The effects of ASD and the severity of symptoms are different in each person. Some people can live independently and work, while more severely affected people will need support with the basic activities of daily life.

Adults and children with autism may:

• Have trouble figuring out what others are thinking or feeling, or have trouble expressing their own feelings
• Struggle to establish and maintain relationships
• Have difficulty understanding or practicing appropriate social behaviors
• Misunderstand double meanings
• Interpret information too literally
• Feel anxious in groups
• Have trouble making eye contact
• Engage in repetitive or routine behaviors
• Find it hard to adapt to a change in routine
• Regress developmentally (lose language or social skills they previously had)
• Repeat words or phrases, also known as echolalia
• Show repetitive movements, such as hand flapping, rocking back and forth, or spinning in circles
• Become upset with minor changes
• Have obsessive interests
• Like parts of toys (e.g., only the wheels of cars)
• Have few to none of the skills needed for social interaction
• Show little sense of safety and lack awareness of danger
• Have unusual reactions, oversensitivity or undersensitivity to sounds, smells, tastes, textures, light or color
• Avoid or resist physical contact
• Have delayed motor skills and appear clumsy or uncoordinated

If someone shows some of these signs, it doesn't necessarily mean they have autism. These are all behaviors that may be explained by several possible conditions, so proper diagnosis will require the expertise of healthcare professionals.

Some children with autism show symptoms as early as 6 months, while others don't have symptoms until they're 2 or 3 years old. The signs for these young children may include:

• Making limited or no eye contact by 6 months
• Showing few or no big smiles or other warm, joyful expressions by 6 months
• Inability to point at objects of interest by 12 months
• Little or no babbling, few back-and-forth gestures, such as waving, or no response to their name by 12 months
• Not saying any or only saying a few words by 16 months
• Not playing pretend games
• Wanting to be alone

Some people with autism may have strong verbal skills and intellectual ability. This condition is known as Asperger's syndrome—sometimes called high-functioning autism—and differs from typical autism in important ways.

There often is no language delay. In fact, people with this form of autism often have good speech and communication skills. However, some may lack inflection in their voice or be too loud, while others with Asperger's may not understand subtle forms of communication, such as irony, humor or maintaining a flow of conversation. Another difference in Asperger’s is the desire to be social, but not knowing how to socialize.

People with Asperger's also have normal or above-normal levels of intelligence. Many often have a deep knowledge of a narrow subject, such as baseball statistics. People with high-functioning autism may have good rote memory skills—they can memorize material without reference to the meaning or context of it—but they may struggle with abstract ideas.

There's a wide variety of symptoms of ASD. The symptoms usually involve problems with communication, social interaction, repetitive behaviors and restricted interests. These may, to varying degrees, affect the ability to function in everyday life. If you or someone you care for has symptoms of autism, contact your healthcare provider.

Published May 2021.