What are the signs and symptoms of autism?

Autism is relatively common. There are various signs and symptoms of autism that can lead people to wonder whether 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,  behaves, interacts and communicates with others. This can ultimately impact their ability to function in everyday life.  Autism spectrum disorder (ASD) is subcategorized based on the specific area of deficit, including those with or without intellectual impairment. ASD occurs in all racial, ethnic, and socioeconomic groups. It is more than three times more common in boys than 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. More severely affected people may need support with activities of daily life.

Some symptoms of autism in adults and children include:

• Trouble figuring out what others are thinking or feeling, or trouble expressing personal feelings
• Struggling to establish and maintain relationships
• Difficulty understanding or practicing appropriate social behaviors
  
• Interpreting information too literally
• Feeling overwhelmed in social situations
• Trouble making eye contact
• Engaging in repetitive or routine behaviors
  
• Difficulty adapting to a change in routine
• Regressing developmentally such as losing language or social skills previously acquired
• Repeating words or phrases
• Repetitive movements, such as hand flapping, rocking back and forth, or spinning in circles
  
• Becoming upset with minor changes
• Obsessive interests
• Liking parts of toys (e.g., only the wheels of cars)
• Showing little sense of safety and lacking awareness of danger
  
• Unusual reactions, such as being over or under sensitive to sounds, smells, tastes, textures, light or color
• Avoiding or resisting physical contact
• Delayed motor skills and appearing clumsy or uncoordinated

If someone shows some of these signs, it doesn't necessarily mean they have autism. These behaviors may also be explained by several possible conditions or normal development. A diagnosis requires the expertise of a healthcare professional. 

Some children with autism may show symptoms as early as 6 months. Others don't have symptoms until they're 2 or 3 years old. Signs of autism in 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 

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.

Updated May 2025.