What are the 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, also known as autism spectrum disorder (ASD), is a group of varying neurological and developmental conditions that can affect the way a person learns, their  behaviors, and their ability to interact and communicate with others, ultimately impacting their ability to function in everyday life.  Autism spectrum disorder (ASD) is subcategorized according to the area of deficit, which includes those with or without intellectual impairment.  ASD occurs in all racial, ethnic, and socioeconomic groups. It is more than 4 times more common among boys than among girls.

ASD 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 may need support with 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 overwhelmed in social situations
• Have trouble making eye contact
• Engage in repetitive or routine behaviors
• Find it hard to adapt to a change in routine
• Regress developmentally such as losing language or social skills they previously had
• Repeat words or phrases
• 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)
• Show little sense of safety and lack an awareness of danger
• Have unusual reactions, such as being over or under sensitive 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 also behaviors that may be explained by several possible conditions or normal development, so diagnosis will require the expertise of a healthcare professional.

Some children with autism may 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
• An 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

It’s not always easy to see how everyday behavior matches up with the diagnostic criteria for ASD, especially among older children and adults who have been coping with being on the spectrum for some time. If you or someone you care for has symptoms of autism, you can seek guidance from your healthcare provider, school or local health department.

Clinically reviewed and updated May 2023.