Autism spectrum disorder (ASD) is a developmental disability that can cause significant social, communication, and behavioral challenges. The term “spectrum” refers to the wide range of symptoms, skills, and levels of impairment that people with ASD can have.

ASD affects people in different ways and can range from mild to severe. People with ASD share some symptoms, such as difficulties with social interaction, but there are differences in when the symptoms start, how severe they are, the number of symptoms, and whether other problems are present. The symptoms and their severity can change over time.

The behavioral signs of ASD often appear early in development. Many children show symptoms by 12 months to 18 months of age or earlier.

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. It is important to note that some people without ASD might also have some of these symptoms. For people with ASD, these characteristics can make life very challenging.

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.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.

ASD affects people of every race, ethnic group, and socioeconomic background. It is four times more common among boys than among girls. The Centers for Disease Control and Prevention (CDC) estimates that about 1 in every 54 children in the U.S. has been identified as having ASD.

The word “autism” has its origin in the Greek word “autos,” which means “self.” Children with ASD are often self-absorbed and seem to exist in a private world in which they have limited ability to successfully communicate and interact with others. Children with ASD may have difficulty developing language skills and understanding what others say to them. They also often have difficulty communicating nonverbally, such as through hand gestures, eye contact, and facial expressions.

The ability of children with ASD to communicate and use language depends on their intellectual and social development. Some children with ASD may not be able to communicate using speech or language, and some may have very limited speaking skills. Others may have rich vocabularies and be able to talk about specific subjects in great detail. Many have problems with the meaning and rhythm of words and sentences. They also may be unable to understand body language and the meanings of different vocal tones. Taken together, these difficulties affect the ability of children with ASD to interact with others, especially people their own age.

Below are some patterns of language use and behaviors that are often found in children with ASD.

• Repetitive or rigid language. Often, children with ASD who can speak will say things that have no meaning or that do not relate to the conversations they are having with others. For example, a child may count from one to five repeatedly amid a conversation that is not related to numbers. Or a child may continuously repeat words he or she has heard—a condition called echolalia. Immediate echolalia occurs when the child repeats words someone has just said. For example, the child may respond to a question by asking the same question. In delayed echolalia, the child repeats words heard at an earlier time. The child may say “Do you want something to drink?” whenever he or she asks for a drink. Some children with ASD speak in a high-pitched or sing-song voice or use robot-like speech. Other children may use stock phrases to start a conversation. For example, a child may say, “My name is Tom,” even when he talks with friends or family. Still others may repeat what they hear on television programs or commercials.
• Narrow interests and exceptional abilities. Some children may be able to deliver an in-depth monologue about a topic that holds their interest, even though they may not be able to carry on a two-way conversation about the same topic. Others may have musical talents or an advanced ability to count and do math calculations. Approximately 10 percent of children with ASD show “savant” skills, or extremely high abilities in specific areas, such as memorization, calendar calculation, music, or math.
• Uneven language development. Many children with ASD develop some speech and language skills, but not to a normal level of ability, and their progress is usually uneven. For example, they may develop a strong vocabulary in a particular area of interest very quickly. Many children have good memories for information just heard or seen. Some may be able to read words before age five, but may not comprehend what they have read. They often do not respond to the speech of others and may not respond to their own names. As a result, these children are sometimes mistakenly thought to have a hearing problem.
• Poor nonverbal conversation skills. Children with ASD are often unable to use gestures—such as pointing to an object—to give meaning to their speech. They often avoid eye contact, which can make them seem rude, uninterested, or inattentive. Without meaningful gestures or other nonverbal skills to enhance their oral language skills, many children with ASD become frustrated in their attempts to make their feelings, thoughts, and needs known. They may act out their frustrations through vocal outbursts or other inappropriate behaviors.

If a doctor suspects a child has ASD or another developmental disability, he or she usually will refer the child to a variety of specialists, including a speech-language pathologist. This is a health professional trained to treat individuals with voice, speech, and language disorders. The speech-language pathologist will perform a comprehensive evaluation of the child’s ability to communicate, and will design an appropriate treatment program. In addition, the speech-language pathologist might make a referral for a hearing test to make sure the child’s hearing is normal.

Teaching children with ASD to improve their communication skills is essential for helping them reach their full potential. There are many different approaches, but the best treatment program begins early, during the preschool years, and is tailored to the child’s age and interests. It should address both the child’s behavior and communication skills and offer regular reinforcement of positive actions. Most children with ASD respond well to highly structured, specialized programs. Parents or primary caregivers, as well as other family members, should be involved in the treatment program so that it becomes part of the child’s daily life.

For some younger children with ASD, improving speech and language skills is a realistic goal of treatment. Parents and caregivers can increase a child’s chance of reaching this goal by paying attention to his or her language development early on. Just as toddlers learn to crawl before they walk, children first develop pre-language skills before they begin to use words. These skills include using eye contact, gestures, body movements, imitation, and babbling and other vocalizations to help them communicate. Children who lack these skills may be evaluated and treated by a speech-language pathologist to prevent further developmental delays.

For slightly older children with ASD, communication training teaches basic speech and language skills, such as single words and phrases. Advanced training emphasizes the way language can serve a purpose, such as learning to hold a conversation with another person, which includes staying on topic and taking turns speaking.

Some children with ASD may never develop oral speech and language skills. For these children, the goal may be learning to communicate using gestures, such as sign language. For others, the goal may be to communicate by means of a symbol system in which pictures are used to convey thoughts. Symbol systems can range from picture boards or cards to sophisticated electronic devices that generate speech through the use of buttons to represent common items or actions.

The federal government’s Autism CARES Act of 2014 brought attention to the need to expand research and improve coordination among all of the components of the National Institutes of Health (NIH) that fund ASD research. These include the National Institute of Mental Health (NIMH), along with the National Institute on Deafness and Other Communication Disorders (NIDCD), the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), the National Institute of Environmental Health Sciences (NIEHS), the National Institute of Neurological Disorders and Stroke (NINDS), the National Institute of Nursing Research (NINR), and the National Center for Complementary and Integrative Health (NCCIH).

Together, five institutes within the NIH (NIMH, NIDCD, NICHD, NIEHS, and NINDS) support the Autism Centers of Excellence (ACE), a program of research centers and networks at universities across the country. Here, scientists study a broad range of topics, from basic science investigations that explore the molecular and genetic components of ASD to translational research studies that test new types of behavioral therapies. Some of these studies involve children with ASD who have limited speech and language skills, and could lead to testing new treatments or therapies. You can visit the NIH Clinical Trials website and enter the search term “autism” for information about current trials, their locations, and who may participate.

The NIDCD supports additional research to improve the lives of people with ASD and their families. An NIDCD-led workshop focused on children with ASD who have limited speech and language skills, resulting in two groundbreaking articles. Another NIDCD workshop on measuring language in children with ASD resulted in recommendations calling for a standardized approach for evaluating language skills. The benchmarks will make it easier, and more accurate, to compare the effectiveness of different therapies and treatments.

NIDCD-funded researchers in universities and organizations across the country are also studying:

• Ways to reliably test for developmental delays in speech and language in the first year of life, with the ultimate goal of developing effective treatments to address the communication challenges faced by many with ASD.
• How parents can affect the results of different types of language therapies for children with ASD.
• Enhanced ways to improve communication between children with and without ASD. This could involve a communication board with symbols and pictures, or even a smartphone app.
• Techniques to help researchers better understand how toddlers with ASD perceive words, and the problems they experience with words.
• Cost-effective ways to prevent or reduce the impact of conditions affecting speech, language, and social skills in high-risk children (for example, younger siblings of children with ASD).
• The development of software to help people with ASD who struggle with speech to communicate complex thoughts and interact more effectively in society.