Key points
- Autism spectrum disorder (ASD) is a developmental disability caused by differences in the brain.
- Some people with ASD have a known difference, such as a genetic condition. Other causes are not yet known.
- Scientists believe there are multiple causes of ASD that act together to change the most common ways people develop. We still have much to learn about these causes and how they impact people with ASD.
- Early intervention services can greatly improve the development of a child with ASD.
Overview
People with ASD may behave, communicate, interact, and learn in ways that are different from most other people. There is often nothing about how they look that sets them apart from other people. The abilities of people with ASD can vary significantly. For example, some people with ASD may have advanced conversation skills whereas others may be nonverbal. Some people with ASD need a lot of help in their daily lives; others can work and live with little to no support.
ASD begins before the age of 3 years and can last throughout a person's life, although symptoms may change over time. Some children show ASD symptoms within the first 12 months of life. In others, symptoms may not show up until 24 months of age or later. Some children with ASD gain new skills and meet developmental milestones until around 18 to 24 months of age, and then they stop gaining new skills or lose the skills they once had.
Signs and symptoms
People with ASD often have problems with social communication and interaction, and restricted or repetitive behaviors or interests. People with ASD may also have different ways of learning, moving, or paying attention. These characteristics can make life very challenging. It is important to note that some people without ASD might also have some of these symptoms.search ,,Signs and Symptoms of Autism Spectrum Disorder
"Learn the Signs. Act Early."
As a parent, you already have what it takes to help your young child learn and grow. CDC has developed materials to help you track your child's developmental milestones and share that progress, or any concerns, with your child's doctor at every check-up.
CDC's "Learn the Signs. Act Early." program aims to improve early identification of developmental delays and disabilities, such as ASD, by promoting early childhood developmental monitoring by families, child care providers, healthcare providers, and others.
Risk factors
There is not just one cause of ASD. Many different factors have been identified that may make a child more likely to have ASD, including environmental, biologic, and genetic factors.
Although we know little about specific causes, the available evidence suggests that the following may put children at greater risk for developing ASD:
- Having a sibling with ASD
- Having certain genetic or chromosomal conditions, such as fragile X syndrome or tuberous sclerosis
- Experiencing complications at birth
- Being born to older parents
Screening and diagnosis
Diagnosing ASD can be difficult since there is no medical test, like a blood test, to diagnose the disorder. Doctors look at the child's behavior and development to make a diagnosis.
ASD can sometimes be detected at 18 months of age or younger. By age 2 years, a diagnosis by an experienced professional can be considered reliable.1 However, many children do not receive a final diagnosis until they are much older. Some people are not diagnosed until they are adolescents or adults. This delay means that people with ASD might not get the early help they need.
Treatment
Current treatments for ASD seek to reduce symptoms that interfere with daily functioning and quality of life. ASD affects each person differently, meaning that people with ASD have unique strengths and challenges and different treatment needs.2 Treatment plans usually involve multiple professionals and are catered to the individual.
What CDC is doing
Promoting early identification of ASD
We naturally think of a child's growth as height and weight, but from birth to 5 years, a child should reach milestones in how they play, learn, speak, act, and move. A delay in any of these areas could be a sign of ASD or other developmental disability.
Through the "Learn the Signs. Act Early." program, CDC and its partners aim to improve early identification of children with ASD and other developmental disabilities by promoting developmental monitoring, so children and families can get the services and support they need.
Understanding risk factors and causes of ASD
CDC's Study to Explore Early Development (SEED) is a multi-year, multi-site study funded by CDC. It began in 2007 as one of the largest studies in the United States to help us learn more about autism spectrum disorder (ASD) and other developmental disabilities in preschool-aged children (ages 2-5 years). Data collected by SEED has been used to explore early behaviors and other factors related to the development of ASD symptoms that impact quality of life. Learning about these factors may shed light on how we can help children with ASD and their families.
In recent years, SEED was expanded to learn more about the health, functioning, and needs of people with ASD and other developmental disabilities as they mature into adolescence and adulthood.
Determining how many people have ASD
There continue to be many children living with ASD who need services and support, both now and as they grow into adolescence and adulthood.
By studying the number of people identified with ASD over time, we can find out if the number is rising, dropping, or staying the same. We can also compare the number of children with ASD in different areas of the country and different groups of people. This information can help us look for causes of ASD.
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It is also over 3 times as common among boys than among girls.
