Autism spectrum disorder

What is autism spectrum disorder?

Autism spectrum disorder (also called ASD) is a developmental disability that can cause major social, communication and behavior challenges. People with ASD may communicate, interact, behave and learn in ways that are different from most other people. Some people with ASD have strong skills in learning, thinking and solving problems; others have severe challenges with these skills. Some people with ASD need a lot of help in their daily lives, but others need less help.

Premature babies (babies born before 37 weeks of pregnancy) may be more likely to show signs or symptoms of ASD than other babies. Health care providers can sometimes detect ASD in a child at 18 months old or younger. By the time a child is 2 years old, a provider may give an ASD diagnosis. But many children don’t get a final diagnosis until they’re much older. This delay means children with ASD may not get the early help they need.

It's really important to learn the signs and symptoms of ASD and get help for your child right away if you think he has ASD. Getting early intervention services as soon as possible can help improve your child’s development. These services can help children from birth through 3 years old learn important skills. Services include therapy to help a child talk, walk, learn self-help skills and interact with others. Visit the Early Childhood Technical Assistance Center to find your state’s contact information for early intervention services.

How common is autism spectrum disorder?

ASD affects about 1 in 59 children in the United States. It affects children of all backgrounds, but it’s almost 4 times more common in boys than in girls. More people are being diagnosed with ASD today than ever before. We’re not sure exactly why, but it may be because of several reasons, including:

• The way health care providers define and diagnose ASD has changed. A diagnosis of ASD now includes several conditions that used to be diagnosed separately, like autistic disorder, pervasive developmental disorder not otherwise specified (PDD-NOS) and Asperger syndrome. Now these conditions are all called ASD.
• In the past, only children with the most severe ASD symptoms were diagnosed. Today children with less severe ASD symptoms are diagnosed.
• People are more aware of ASD. More families know the signs and symptoms of ASD, so more children are checked for it. More providers are screening for ASD now than in the past.
• Schools are more aware and are able to help identify signs and help children receive more special education services.

How do you know if your child has autism spectrum disorder?

ASD can be hard to diagnose. There’s no medical test, like a blood test, to check for ASD. No two children with ASD have the exact same signs or symptoms. Providers diagnose ASD by looking at your child’s behavior and development.

Children with ASD usually show signs or symptoms when they’re 12 to 24 months old, but some may have them earlier or later. Some children with ASD develop normally until they’re around 18 to 24 months old, but then they stop gaining new skills or lose the skills they once had. This is called regression.

Babies may show signs of ASD before their first birthday if they have severe developmental delays. Developmental delays are when your child doesn’t reach developmental milestones when expected. A developmental milestone is a skill or activity that most children can do at a certain age. Milestones include sitting, walking, talking, having social skills and having thinking skills.

Tell your baby’s health care provider if she isn’t meeting her milestones. It’s not unusual for a healthy baby to fall behind in some areas or move ahead in others. But babies who don’t meet these milestones need their development checked more closely by a provider:

• Babbling by 12 months
• Making gestures (like pointing or waving bye-bye) by 12 months
• Using single words by 16 months
• Using two-word phrases by 24 months
• Losing language or social skills at any age

Most children with ASD don’t have problems with early developmental milestones, like crawling and walking on time. But they may have delays in other areas, like communication, social and behavior skills. If your child shows signs or symptoms of ASD, it doesn’t always mean he has ASD. Children with ASD may have different signs and symptoms, and they may not have all the signs and symptoms.

What is joint attention?

Problems with joint attention are one of the most early and common signs of ASD. Joint attention is when your child looks back and forth between an object (or event) and a person. When a child does this to share interest and interact with another person, he develops skills that help him connect with other people. Most children with ASD have delays in joint attention skills, or they don’t have any joint attention skills.

These are examples of how children with ASD may show different joint attention skills:

• At about 10 to 12 months old: When a parent points at an object (like a toy), most children quickly look towards the object and then look back to their parent. The child imitates (copies) the parent’s facial expression; if the parent is smiling, the child smiles back. Children with ASD may ignore the parent instead of smiling back.
• At 12 to 14 months old: If child wants a toy or another object that they’re interested in but can’t reach, most children point to it. Instead of pointing to an object, a child with ASD may bring her parent to the object, while avoiding eye contact. Or the child may take her parent’s hand and place it on the object, instead of pointing to it. 
• At 14 to 16 months old: Most children can point at objects and look back and forth between objects and their parents. This helps them show their interest in an object and share the experience with a parent. A child with ASD doesn’t look at an object together with her parent. Instead, the child points to an object only so the parent gets it for her.

What are other signs and symptoms of autism spectrum disorder?

A child with ASD may have challenges in communication, social and behavior skills, including:

Communication challenges

• Has delayed speech and language skills. Some children with ASD can’t speak at all or speak very little. About 40 in 100 (40 percent) children with ASD don’t speak at all. Other children with ASD speak well. 
• Has trouble talking to other people, starting a conversation and sharing his needs using typical words or motions like pointing. A child with ASD may talk a lot about something he really likes rather than have a conversation with another person.
• Doesn’t understand jokes, teasing or sarcasm. Sarcasm means using bitter or teasing words to make fun of someone or something.
• Mixes up pronouns (says “you” instead of “I”)
• Repeats or echoes words or phrases 
• Seems unaware when people talk to him, but responds to other sounds
• Talks in a flat, robot-like voice or talks in a sing-song or high-pitched voice

Social challenges

• Avoids eye contact or makes very little eye contact
• Doesn’t respond to his name by 12 months old
• Doesn’t respond to a parent’s smile or other facial expressions, or makes facial expressions that aren’t appropriate
• Doesn’t look at objects when someone points to them or doesn’t point at objects to show interest (like pointing at an airplane flying in the sky)
• Has trouble understanding other people’s feelings, has trouble talking about his own feelings or doesn’t show concern (also called empathy) for others
• Is interested in people, but doesn’t know how to talk, play or relate to them
• Wants to be alone or play alone, has trouble making friends or doesn’t have an interest in other people at all

Behavior challenges

• Doesn’t play “pretend” games (like pretending to feed a doll), or plays with parts of a toy instead of the whole toy
• Gets upset by changes in routines, like making an unplanned stop on the way home from school
• Has unusual interests or behaviors, like lining up toys or objects without playing with them or being really interested in vacuum cleaners
• Is very sensitive or not sensitive at all to the way things feel, sound, taste or smell. Some children with ASD seem as though they don’t feel pain, heat or cold, and some don’t want to be held, cuddled or touched. Others are super sensitive to everyday sounds and cover their ears or hide from sounds.
• Some children need extra stimulation, such as firm hugs or the comfort of being covered by a heavy blanket in bed.
• Is overly focused on one thing or activity and does the activity many times during a day
• Is very interested in certain things, like numbers, symbols or certain subjects, and remembers lots of information about these things
• Repeats actions over and over again, like flapping his hands, spinning in circles, rocking his body or walking on his toes

Other challenges or signs

• Is hyperactive (far more active than others) or has trouble sitting still or paying attention
• Is impulsive (acts without thinking first)
• Isn’t afraid of dangerous things but is very afraid of harmless things
• Is violent
• Has temper tantrums often or hurts himself, like by banging his head or biting himself
• Has different eating or sleeping habits. Some children with ASD may eat just a few foods. Others may want to eat nonfoods, like dirt or rocks. This kind of eating problem is called pica.
• May have a good memory, especially for numbers, letters, songs, TV jingles or a specific topic

What is developmental monitoring?

At each well-child visit, your baby’s provider looks for developmental delays or problems and talks with you about any concerns you may have about your baby’s development. This is called developmental monitoring or surveillance. The provider monitors (checks) your child as a baby through school age and even later in life if he has problems with social, learning or behavior skills. If your baby has any problems that come up during developmental monitoring, he needs developmental screening.

What is developmental screening?

Developmental screening is a short test that checks to see if a child is learning basic skills when he should, or if there are delays. During developmental screening, your baby’s provider does a short checkup to look for signs of problems. During screening, the provider may ask you some questions or talk and play with your baby to see how he plays, learns, speaks, behaves and moves. A delay in any of these areas could be a sign of a problem. The American Academy of Pediatrics (AAP) recommends that all children be screened for developmental delays and disabilities during regular well-child visits at:

• 9 months
• 18 months
• 24 or 30 months

If your child’s provider doesn’t do this kind of developmental screening, you can ask the provider that it be done. Some babies may need extra screening if they’re at high risk for developmental problems because they were born prematurely or with low birthweight (less than 5 pounds, 8 ounces) or because of other reasons, like having a brother or sister with ASD. If the provider thinks your baby may have ASD, she needs a full evaluation before a diagnosis can be made.

How is autism spectrum disorder diagnosed?

Different health care providers evaluate your child to help diagnose ASD. Providers include:

• Developmental pediatrician. This is a pediatrician who has special training in child development and taking care of children with special needs.
• Child neurologist. This is a doctor who treats the brain, spine and nerves in children.
• Child psychiatrist or child psychologist. These are mental health professionals who have special training to take care of children with emotional or mental health problems. 
• Occupational therapist. This is a specialist who helps people learn to carry out everyday activities. For children, this may be things like brushing teeth, getting dressed, putting on shoes or learning to use a pencil.  
• Physical therapist. This is a specialist who creates exercise programs to help build strength and help with movement.
• Speech therapist. This is a specialist who helps people with speech and language problems. For children this may include helping with saying sounds or words correctly and completely. It can also include in helping children be understood and also understand others.  

To evaluate your child, the providers may: 

• Talk with you about your child’s health and development history 
• Watch your child play and interact with you
• Give your child a physical exam and hearing test. Any child with a speech delay or possible ASD should have a hearing test. 
• Check your child’s developmental skills, including motor (movement) skills, language skills, social skills and cognitive skills. Motor skills include walking and writing. Cognitive skills are learning, thinking and problem-solving skills. A child may have ASD if her social and language skills are much weaker than her motor and cognitive skills. 
• Evaluate your child’s language skills by checking her speech, pronunciation (the way words are said) and how she follows social rules for language (like using facial expressions and eye contact, or taking turns in conversation)

Your child’s providers may use medical tests to see if your child has a medical condition with signs or symptoms that are similar to ASD. These include:

• Genetic tests to check for conditions, like fragile X syndrome or Rett syndrome. Rett syndrome has some similarities to ASD.  It is a rare genetic disease that mostly affects girls and causes problems in development and the nervous system (brain, spine and nerves). 
• Tests to check the levels of lead in your child’s blood. High levels of lead can cause serious problems, like brain damage and developmental delays.
• Electroencephalogram (also called EEG) or magnetic resonance imaging (also called MRI). EEG records electrical activity in your baby’s brain. MRI uses radio waves and magnets to make a picture of your baby’s brain.
• Tests to check for metabolic disorders. These are health conditions that affect a body’s metabolism. Metabolism is the way your body changes food into the energy it needs to breathe, digest food and grow. They can cause intellectual and developmental disabilities. 

How is autism spectrum disorder treated?

There is no cure for ASDs. But some children can do well when they get treatment as soon as possible. In addition to early intervention services, children with ASD may need other kinds of treatment, including:

Medicines. While medicines can’t cure ASD, certain medicines can help some children with ASD to function better. No two children with ASD are exactly alike, but talk to your child’s provider to see if any medicines may help your child.

Early Intervention Services. Early intervention services can help children from birth to 3 years old (36 months) learn important skills. Services include therapy to help the child talk, walk and interact with others. Visit the Early Childhood Technical Assistance Center to find your state’s contact information for early intervention services

Behavior and communication treatment options and therapies. These include:

• Applied behavior analysis (also called ABA) is a treatment approach that encourages positive behaviors and discourages negative behaviors to help a child improve in certain skills. During ABA, a trainer asks a child to do something and gets a response (behavior) from the child. If the child responds with the right behavior, he gets a reward, like a toy or candy. Providers track and measure the child’s progress. Providers and therapists at many schools and clinics use ABA. There are different types of ABA.
• Developmental, individual differences, relationship-based approach (also called DIR or “floortime”). This kind of therapy helps a child understand feelings and establish relationships with caregivers. It also focuses on how a child deals with sights, sounds and smells. This therapy is done on the floor at the child’s level. Children play with therapists and parents to help develop their skills and relationships. 
• Occupational therapy. This helps a child learn skills like dressing, eating, bathing, interacting with others and relating to people.
• Sensory integration therapy. This is a kind of occupational therapy that helps a child deal with sensory information, like sights, sounds and smells. It may help a child who is bothered by certain sounds or who doesn’t like to be touched. It can also help with feeding problems.
• Speech and language therapy. This helps a child learn communication skills, like understanding language and being able to express himself through speech. Therapists often use picture boards and gestures to help a child develop these skills. 
• The picture exchange communication system (also called PECS). This uses pictures or symbols to teach communication skills. Children learn to use picture symbols to ask and answer questions and have a conversation.
• Treatment and education of autistic and related communication-handicapped children (also called TEACCH). TEACCH uses visual cues to teach skills. For example, picture cards can help teach a child how to get dressed by breaking down the information into small steps.

Complementary and alternative medicine. To help manage or relieve ASD symptoms, some parents and providers use treatments that are different from what a pediatrician typically recommends. These are called complementary and alternative medicine (also called CAM). 

Special diets are one kind of CAM for children with ASD, but there isn’t enough research to recommend them. These diets are based on the idea that food allergies, food sensitivities or not getting enough vitamins and minerals through food can cause ASD signs and symptoms. A food allergy is when you have an abnormal response to a food because it triggers your body’s immune system. Symptoms of a food allergy may include hives, rash, or itching or swelling in your mouth. A food sensitivity is when you don’t feel great or have a minor reaction after eating a food. A food sensitivity is less serious than a food allergy. Symptoms of a food sensitivity may include having stomach cramps or stomach pain. Some parents feel that changes in food make a difference in how their child acts or feels. Talk with your child’s provider before making any changes to the foods he eats. 

Other CAM treatments have not been studied and may be dangerous. Before starting any treatment, talk to your child’s provider.

What causes autism spectrum disorder or increases risk?

We don’t know all the causes of ASD. Research suggests that ASD may develop in a child around the time of birth—before, during and immediately after. More research is needed, but these things may play a role:

• Having pregnancy complications. Some research shows that there may be a link between ASD and pregnancy complications that lead to low birthweight, premature birth or cesarean birth. 
• Taking certain prescription medicines, like valproic acid or thalidomide, during pregnancy. Taking these medicines during pregnancy has been linked with a higher risk of having a child with ASD.
• Having an older parent. Babies born to older parents are more likely to have ASD. 
• Having a sibling with ASD.  Children with a sibling who has ASD are at higher risk of also having ASD.  
• Having genes linked to ASD. Researchers are studying a number of genes that may be linked to ASD. A gene is a part of your body’s cells that stores instructions for the way your body grows and works. Genes are passed from parents to children. 
• Having a genetic or chromosomal condition. A genetic condition is caused by a gene that’s changed from its regular form. A gene can change on its own, or the changed gene can be passed from parents to children. ASD happens more often in children who also have certain genetic or chromosomal conditions, like Fragile X syndrome or tuberous sclerosis. Fragile X syndrome is a condition that happens when the body can’t make enough of a protein it needs for the brain to grow and develop. Tuberous sclerosis is a rare genetic condition that causes tumors to grow in the brain and other organs. 

Do vaccinations cause autism spectrum disorder?

No. Vaccines your baby gets do not cause autism. You may have heard about vaccines that contain thimerosal, a chemical that has mercury in it. Research shows that thimerosal in vaccines does not cause autism. Thimerosal is no longer used in vaccines, except in some flu shots. But you can get a thimerosal-free flu vaccine for your child if you want. If you need more information, talk to your baby’s provider.

More information

• American Academy of Pediatrics (AAP)
• Centers for Disease Control and Prevention (CDC) development
• National Institute of Mental Health (NIMH)
• National Institute of Neurological Disorders and Stroke (NINDS)

Last reviewed: February, 2020