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.

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 improve 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.

As children with ASD become adolescents and young adults, they may have difficulties developing and maintaining friendships, communicating with peers and adults, or understanding what behaviors are expected in school or on the job. They may come to the attention of healthcare providers because they also have conditions such as anxiety, depression, or attention-deficit/hyperactivity disorder, which occur more often in people with ASD than in people without ASD.

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.

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, 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.

Risk Factors

There is not just one cause of ASD. There are many different factors that 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

CDC is currently working on one of the largest U.S. studies to date on ASD. This study called the Study to Explore Early Development (SEED), was designed to look at the risk factors and behaviors related with ASD.  CDC is now conducting a follow-up study of older children who were enrolled in SEED to determine the health, functioning, and needs of people with ASD and other developmental disabilities as they mature.

How Often ASD Occurs

CDC’s Autism and Developmental Disabilities Monitoring (ADDM) Network has been estimating the number of 8-year-old children with ASD in the United States since 2000.

ASD occurs in all racial, ethnic, and socioeconomic groups. It is more than 4 times more common among boys than among girls.

If You’re Concerned

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.

Contact your child’s doctor if you think your child might have ASD or if you have any other concerns about the way your child plays, learns, speaks, or acts.

If you are still concerned, ask the doctor for a referral to a specialist who can do a more in-depth evaluation of your child. Specialists who can do a more in-depth evaluation and make a diagnosis include

• Developmental pediatricians (doctors who have special training in child development and children with special needs)
• Child neurologists (doctors who work on the brain, spine, and nerves)
• Child psychologists or psychiatrists (doctors who know about the human mind)

At the same time, call your state’s public early childhood system to request a free evaluation, sometimes called a Child Find evaluation, to find out if your child qualifies for intervention services.  You do not need to wait for a doctor’s referral or a medical diagnosis to make this call.

Where to call for a free evaluation from the state depends on your child’s age:

• If your child is not yet 3 years old, contact your local early intervention system.
  • You can find the right contact information for your state by calling the Early Childhood Technical Assistance Center (ECTA) at 919-962-2001.
• If your child is 3 years old or older, contact your local public school system.
  • Even if your child is not yet old enough for kindergarten or enrolled in a public school, call your local elementary school or board of education and ask to speak with someone who can help you have your child evaluated.
  • If you’re not sure who to contact, call the ECTA at 919-962-2001.

Research shows that early intervention services can greatly improve a child’s development. In order to make sure your child reaches their full potential, it is very important to receive services as soon as possible.

If someone in your family has autism spectrum disorder (ASD), you may be more likely to have a child with ASD. ASD can look very different from person to person, so taking a careful family health history can be important for early diagnosis. Early screening and diagnosis of ASD can ensure that children receive the services they need for better outcomes.

What is autism spectrum disorder?

Autism spectrum disorder (ASD) is a developmental disorder. Someone with ASD may have difficulty with social interaction, communication, and behavior. For example, the earliest signs of ASD are that children may not make eye contact with their parents and may not be aware when someone is talking to them. About 30% of people (about 1 in 3) with ASD have an intellectual disability.

What causes autism spectrum disorder?

Although the cause of ASD is known in some people and not known in others, genetics, biology, and environment are all important factors. Having older parents, a difficult birth, or infections during pregnancy are all examples of factors that might increase the risk for having ASD. Beyond these factors, certain people are at higher risk than others. For example, ASD is four times more common in males than females. People with certain genetic disorders, such as fragile X syndrome, tuberous sclerosis, and Down syndrome, are more likely to have ASD.

Why is it important to know if you have a family health history of autism spectrum disorder?

Having a family health history of ASD makes you more likely to have a child with ASD, or to have ASD yourself. If you have a child with ASD, you are more likely to have another child with ASD, especially if you have a daughter with ASD or more than one child with ASD. Your other family members would also be more likely to have a child with ASD.

If you are pregnant or planning a pregnancy, tell your doctor if you or your partner have a family health history of ASD. This information can help your doctor determine how likely you are to have a child with ASD.

When collecting family health history information,

• Include your and your partner’s children, parents, sisters, brothers, grandparents, aunts, uncles, nieces, and nephews;
• Include anyone with a diagnosis of ASD, learning disorder, intellectual disability, schizophrenia, epilepsy/seizures, personality disorder, or attention-deficit/hyperactivity disorder (ADHD);
• Note if anyone had genetic testing and the results of that testing;
• Include anyone with a genetic disorder that can cause ASD, such as fragile X syndrome or Rett syndrome;
• Be sure to include anyone who received a diagnosis that is no longer used, such as Asperger syndrome or mental retardation; and
• Consider including older family members who have or had signs of ASD, even if they were not diagnosed with ASD, as ASD diagnoses were less common in the past and might have been missed.

Be sure to share your family health history of ASD with your child’s doctor and other family members.

What might the doctor recommend for your child if you have a family health history of autism spectrum disorder?

Knowing about your family health history of ASD can help your child’s doctor better care for your child. The doctor may check your child more closely for early signs of ASD and might refer your child to a specialist for further evaluation. When a child is closely monitored, signs of ASD can sometimes be noticed at 18 months or younger. A reliable diagnosis of ASD is more common around 2 or 3 years of age and usually made by a developmental specialist. If a child is diagnosed at a young age with ASD, treatment is more effective. Also, a diagnosis of ASD is important for tailoring children’s education once they start school. Learn how early intervention leads to better outcomes for children with ASD.

If you are pregnant or planning a pregnancy, your doctor might recommend carrier screening if you have a family health history of a genetic disorder, such as fragile X syndrome.

Genetic testing and autism spectrum disorder

If your child is diagnosed with ASD, the doctor might refer your child for genetic counseling and testing. Genetic testing looks for causes of ASD but cannot be used to diagnose ASD. Some people with ASD have syndromic ASD, meaning that they have other specific features in addition to having ASD, such as looking different from other people in the family or having birth defects. Most people with syndromic ASD have a genetic cause for their ASD.

Genetic testing is more likely to find a genetic cause for ASD if

• Your child or another family member has syndromic ASD;
• A family member has an ASD-related genetic change found through genetic testing; or
• Multiple family members have ASD.

The most commonly ordered test for people with ASD is called a chromosomal microarray (CMA). This test looks at chromosomes to see if there are extra or missing parts that could cause ASD. CMA finds a genetic cause in 5% to 14% of people with ASD who have the test.

In addition, children with ASD should be checked for genetic disorders that can cause ASD, including the following:

• Fragile X syndrome: This disorder is one of the most common causes of intellectual disability. Fragile X syndrome affects about 1 in 7,000 males and about 1 in 11,000 females. About 0.5% of people (1 in 200) with ASD have fragile X syndrome. Testing for fragile X syndrome is recommended for all people with ASD.
• Rett syndrome: This disorder mainly affects females. About 4% of females with ASD have Rett syndrome. Rett syndrome testing should be considered for females with ASD.

If CMA and genetic testing do not find a cause for ASD, whole exome sequencing might be recommended. Whole exome sequencing looks for genetic changes in the parts of DNA that act as instructions for making proteins. Whole exome sequencing finds a cause in 8% to 20% of people with ASD who have the text.

After genetic testing, genetic counseling is important to help you understand the test results and what they mean for your child and family. Genetic testing results can give doctors useful information about how to treat your child with ASD and which family members might be more likely to have a child with ASD.

Even if you don’t have a family history of ASD, talk to your child’s doctor if you have concerns about your child’s development.

Diagnosing autism spectrum disorder (ASD) can be difficult because there is no medical test, like a blood test, to diagnose the disorder. Doctors look at the child’s developmental history and behavior to make a diagnosis.

ASD can sometimes be detected at 18 months of age or younger. By age 2, a diagnosis by an experienced professional can be considered reliable . However, many children do not receive a final diagnosis until 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.

Diagnosing children with ASD as early as possible is important to make sure children receive the services and supports they need to reach their full potential . There are several steps in this process.

Developmental Monitoring

Developmental monitoring is an active, ongoing process of watching a child grow and encouraging conversations between parents and providers about a child’s skills and abilities. Developmental monitoring involves observing how your child grows and whether your child meets the typical developmental milestones, or skills that most children reach by a certain age, in playing, learning, speaking, behaving, and moving.

Parents, grandparents, early childhood education providers, and other caregivers can participate in developmental monitoring. CDC’s Learn the Signs. Act Early. program has developed free materials, including CDC’s Milestone Tracker app, to help parents and providers work together to monitor your child’s development and know when there might be a concern and if more screening is needed. You can use a brief checklist of milestones to see how your child is developing. If you notice that your child is not meeting milestones, talk with your doctor or nurse about your concerns and ask about developmental screening. Learn more about CDC Milestone Tracker app, milestone checklists, and other parent materials.

When you take your child to a well visit, your doctor or nurse will also do developmental monitoring. The doctor or nurse might ask you questions about your child’s development or will talk and play with your child to see if they are developing and meeting milestones.

Your doctor or nurse may also ask about your child’s family history. Be sure to let your doctor or nurse know about any conditions that your child’s family members have, including ASD, learning disorders, intellectual disability, or attention deficit/hyperactivity disorder (ADHD).

Developmental Screening

Developmental screening takes a closer look at how your child is developing.

Developmental screening is more formal than developmental monitoring. It is a regular part of some well-child visits even if there is not a known concern.

The American Academy of Pediatrics (AAP) recommends developmental and behavioral screening for all children during regular well-child visits at these ages:

• 9 months
• 18 months
• 30 months

In addition, AAP recommends that all children be screened specifically for ASD during regular well-child visits at these ages:

• 18 months
• 24 months

Screening questionnaires and checklists are based on research that compares your child to other children of the same age. Questions may ask about language, movement, and thinking skills, as a well as behaviors and emotions. Developmental screening can be done by a doctor or nurse, or other professionals in healthcare, community, or school settings. Your doctor may ask you to complete a questionnaire as part of the screening process. Screening at times other than the recommended ages should be done if you or your doctor have a concern.  Additional screening should also be done if a child is at high risk for ASD (for example, having a sibling or other family member with ASD) or if behaviors sometimes associated with ASD are present. If your child’s healthcare provider does not periodically check your child with a developmental screening test, you can ask that it be done.

Developmental Diagnosis

A brief test using a screening tool does not provide a diagnosis, but it can indicate whether a child is on the right development track or if a specialist should take a closer look. If the screening tool identifies an area of concern, a formal developmental evaluation may be needed. This formal evaluation is a more in-depth look at a child’s development and is usually done by a trained specialist such as a developmental pediatrician, child psychologist, speech-language pathologist, occupational therapist, or other specialist. The specialist may observe the child give the child a structured test, ask the parents or caregivers questions, or ask them to fill out questionnaires. The results of this formal evaluation highlight your child’s strengths and challenges and can inform whether they meet criteria for a developmental diagnosis.

A diagnosis of ASD now includes several conditions that used to be diagnosed separately; autistic disorder, pervasive developmental disorder not otherwise specified (PDD-NOS), and Asperger syndrome. Your doctor or other healthcare provider can help you understand and navigate the diagnostic process.

The results of a formal developmental evaluation can also inform whether your child needs early intervention services. In some cases, the specialist might recommend genetic counseling and testing for your child.

Act early on developmental concerns to make a real difference for your child and you! If you’re concerned about your child’s development, don’t wait. You know your child best.

Early intervention helps children improve their abilities and learn new skills. Take these steps to help your child today:

1. Tell your child’s doctor or nurse if you notice any signs of possible developmental delay and ask for a developmental screening.

If you or the doctor still feel worried,

2. Ask for a referral to a specialist, and
3. Call your state or territory’s early intervention program to find out if your child can get services to help.

What is Early Intervention?

Early intervention:

• Is the term used to describe services and support that help babies and toddlers (from birth to 3 years of age in most states/territories) with developmental delays or disabilities and their families.
• May include speech therapy, physical therapy, and other types of services based on the needs of the child and family.
• Can have a significant impact on a child’s ability to learn new skills and increase their success in school and life.
• Programs are available in every state and territory. These services are provided for free or at a reduced cost for any child who meets the state’s criteria for developmental delay.

Why Early Intervention is Important

Earlier is better!

Intervention is likely to be more effective when it is provided earlier in life rather than later.

“If it’s autism, waiting for a child to ‘catch up on his own’ just won’t work. Acting early can help a child communicate, play, and learn from the world now and for the future. It can also prevent frustration—so common in children with communication difficulties—from turning into more difficult behaviors.”  Pennsylvania clinical psychologist

The connections in a baby’s brain are most adaptable in the first three years of life. These connections, also called neural circuits, are the foundation for learning, behavior, and health. Over time, these connections become harder to change.

“The earlier developmental delays are detected and intervention begins, the greater the chance a young child has of achieving his or her best potential.”  Georgia pediatrician

Intervention works!

Early intervention services can change a child’s developmental path and improve outcomes for children, families, and communities.

“Acting early gives your child a chance to receive the appropriate therapy, giving him or her the best chance for a good outcome in the future. I believe that early intervention is the reason my high-functioning son is now able to blend in with his peers and attend kindergarten in a regular classroom with no supports.”  Kansas mom

Help your child, help your family!

Families benefit from early intervention by being able to better meet their children’s needs from an early age and throughout their lives.

“Action replaced fear and empowered me with the knowledge to help my son. He has overcome most of his symptoms and is headed to college next year.”  Florida mom

To find your state or territory’s early intervention contact information, go to cdc.gov/FindEI

The following tips will help you talk with your child’s doctor’s office and the evaluation centers.

Doctor’s Office

When you call your child’s doctor’s office, say, “I would like to make an appointment to see the doctor because I am concerned about my child’s development.”

Be ready to share your specific concerns about your child when you call. If you wrote down notes about your concerns, keep them. Your notes will be helpful during your visit with the doctor.

Early Intervention Services Office

When you call your state’s early intervention services office (if your child is not yet 3 years old), say, “I am concerned about my child’s development and would like to request an evaluation. Can you help me or let me speak with someone who can?”

• Be ready to share your specific concerns about your child. You will also be asked for some general information about yourself and your child (your name, your child’s name and age, where you live, and more).
• Write down who you speak to, the date, and what was said; you might need this information later.

Elementary School or Board of Education

When you call your local elementary school or board of education (if your child is 3 or older), say, “I am concerned about my child’s development and would like to talk with someone about having my child evaluated. Can you help me or let me speak with someone who can?”

• Be ready to share your specific concerns about your child. You will also be asked for some general information about yourself and your child (your name, your child’s name and age, where you live, and more).
• Write down who you speak to, the date, and what was said; you might need this information later.

While You Wait

If you have to wait to get an appointment to see a specialist or start intervention services, know that there are some simple things you can do today and everyday to help your child’s development.

Unfortunately, families may have to wait many weeks or sometimes months before they are able to get an appointment to see a specialist or start intervention services for their child’s developmental problem. This can be a frustrating time for parents who want answers and help now.

If you find yourself in this situation, know that there are some simple things you can do today and everyday to help your child’s development.

Make the Most of Playtime

Interact with your child as much as possible. Read books, sing songs, play with toys, make crafts, do household chores, and play outside together. Talk to your child: label items, point out interesting things, tell stories, comment about what you see and how you feel, and explain how things work and why things happen. Your child may not always seem to be listening, but he or she may be hearing more than you think.

Find Support

Reach out. You are not alone. To find support and information for your family, visit the Family Voices website or call 1-888-835-5669.

There is currently no one standard treatment for autism spectrum disorder (ASD).

Many people with ASD benefit from treatment, no matter how old they are when they are diagnosed. People of all ages, at all levels of ability, can often improve after well-designed interventions.

But there are many ways to help minimize the symptoms and maximize abilities. People who have ASD have the best chance of using all of their abilities and skills if they receive appropriate therapies and interventions.

The most effective therapies and interventions are often different for each person. However, most people with ASD respond best to highly structured and specialized programs. In some cases, treatment can greatly reduce symptoms and help people with autism with daily activities.

Research shows that early diagnosis and interventions, such as during preschool or before, are more likely to have major positive effects on symptoms and later skills. Read more about early interventions for autism.

Because there can be overlap in symptoms between ASD and other disorders, such as attention deficit hyperactivity disorder (ADHD), it's important that treatment focus on a person's specific needs, rather than the diagnostic label.

Treatment for ASD:

• Behavioral management therapy
• Cognitive behavior therapy
• Early intervention
• Educational and school-based therapies
• Joint attention therapy
• Medication treatment
• Nutritional therapy
• Occupational therapy
• Parent-mediated therapy
• Physical therapy
• Social skills training
• Speech-language therapy