Autism spectrum disorder
Autism; Autistic disorder; Asperger syndrome; Childhood disintegrative disorder; Pervasive developmental disorder
Autism spectrum disorder (ASD) is a developmental disorder. It often appears in the first 3 years of life. ASD affects the brain's ability to develop normal social and communication skills.
The exact cause of ASD isn't known. It's likely that a number of factors lead to ASD. Research shows that genes may be involved, since ASD runs in some families. Certain medicines taken during pregnancy may also lead to ASD in the child.
Other causes have been suspected, but not proven. Some scientists believe that damage to a part of the brain, called the amygdala, may be involved. Others are looking at whether a virus may trigger symptoms.
Some parents have heard that vaccines may cause ASD. But studies have found no link between vaccines and ASD. All expert medical and government groups state that there is no link between vaccines and ASD.
The increase in children with ASD may be due to better diagnosis and newer definitions of ASD. Autism spectrum disorder now includes syndromes that used to be regarded as separate disorders:
Every child has a unique personality. Some are outgoing, while others are shy. But there are certain kids who have trouble dealing with things that most children take in stride. They may not make eye contact or have conversations. They may not like to be touched or to hear loud sounds. If you have a child who acts this way, the problem may be autism. Why do kids get autism? Autism is a developmental problem that often becomes noticeable during the toddler years, though it may start earlier. It's significantly more common in premature babies. We know it has to do with abnormal brain biology or chemicals, although the precise mechanism hasn't yet been worked out. Autism appears to be linked both to genes and environmental exposures. Although the cause of autism is still unclear, doctors do know that the recent increase in autism isn't caused by vaccines. Two leading health organizations, the American Academy of Pediatrics and The Institute of Medicine have studied the issue in depth. The recommended vaccines don't increase autism; they do prevent serious diseases like measles, tetanus, and diphtheria. How is autism diagnosed? More kids are getting diagnosed with autism today than they were a few decades ago. Some of this increase may just be that doctors are testing for it more often now. Children with autism share several characteristics. They may be overly sensitive to sounds, sights, smells, or tastes. For example, a child with autism might refuse to wear anything that's the color blue, or scream when he hears a fire engine siren. Get stuck in routines--a child with autism may want to brush his teeth at exactly 9 a.m. every morning, and get upset if he hasn't brushed them by 9:05. They may prefer to play alone, have trouble talking to people and making eye contact. They may also perform the same motions over and over again, such as waving their arms. Lastly, they may be much quieter than other kids his or her age. Doctors can diagnose autism with one or more screening tests. These tests evaluate the child's ability to talk, move, and think. Because each child with autism is different, treatment is tailored to the child. Programs like applied behavioral analysis that can help kids learn the skills they need to be more independent. Medicines can treat specific symptoms that are common in kids with autism, like aggression, hyperactivity, and trouble sleeping. Some kids with autism may respond well to a gluten- or casein-free diet. Gluten is found in breads and other foods that contain wheat, rye, or barley. Casein is an ingredient in dairy products. Talk to a dietitian before making any changes to your child's diet. It's fine to try different autism treatments, but watch out for any program that claims to be a miracle, or a cure. Anything that sounds too good to be true probably is. Autism treatment has come a long way. Decades ago, kids with autism were put away in institutions. Today, they're treated with the goal of becoming independent, functioning adults. If you're worried that your child is showing signs of autism, call your doctor. Get a diagnosis so you can start your child on treatment as soon as possible.
Most parents of ASD children suspect that something is wrong by the time the child is 18 months old. Children with ASD often have problems with:
- Pretend play
- Social interactions
- Verbal and nonverbal communication
Some children seem normal before age 1 or 2. They then suddenly lose language or social skills they already had.
Symptoms can vary from moderate to severe.
A person with autism may:
- Be very sensitive to sight, hearing, touch, smell, or taste (for example, they refuse to wear "itchy" clothes and get upset if they're forced to wear the clothes)
- Be very upset when routines are changed
- Repeat body movements over and over
- Be unusually attached to things
Communication problems may include:
- Can't start or maintain a conversation
- Uses gestures instead of words
- Develops language slowly or not at all
- Doesn't adjust gaze to look at objects that others are looking at
- Doesn't refer to self the right way (for example, says "you want water" when the child means "I want water")
- Doesn't point to show other people objects (normally occurs in the first 14 months of life)
- Repeats words or memorized passages, such as commercials
Social interaction problems may include:
- Doesn't make friends
- Doesn't play interactive games
- Is withdrawn
- May not respond to eye contact or smiles, or may avoid eye contact
- May treat others as objects
- Prefers to be alone rather than with others
- Isn't able to show empathy
Response to sensory information problem may include:
- Doesn't startle at loud noises
- Has very high or very low senses of sight, hearing, touch, smell, or taste
- May find normal noises painful and hold their hands over their ears
- May withdraw from physical contact because it's too stimulating or overwhelming
- Rubs surfaces, mouths or licks objects
- May have a very high or very low response to pain
Problems with play may include:
- Doesn't imitate the actions of others
- Prefers solitary or ritualistic play
- Shows little pretend or imaginative play
Behaviors may include:
- Acts out with intense tantrums
- Gets stuck on a single topic or task
- Has a short attention span
- Has very narrow interests
- Is overactive or very passive
- Is aggressive toward others or self
- Shows a strong need for things being the same
- Repeats body movements
Exams and Tests
All children should have routine exams done by their pediatrician or family clinician. More tests may be needed if the health care provider or parents are concerned. This is true if a child doesn't meet any of these language milestones:
- Babbling by 12 months
- Gesturing (pointing, waving bye-bye) by 12 months
- Saying single words by 16 months
- Saying two-word spontaneous phrases by 24 months (not just echoing)
- Losing any language or social skills at any age
These children might need a hearing test, blood lead test, and screening test for ASD.
A provider experienced in diagnosing and treating ASD should see the child to make the actual diagnosis. Because there isn't a definitive test for ASD, diagnosis is often based on guidelines from a medical book titled Diagnostic and Statistical Manual of Mental Disorders (DSM-V).
An evaluation of ASD often includes a complete physical and nervous system (neurologic) exam. Tests may be done to see if there is a problem with genes or the body's metabolism. Metabolism is the body's physical and chemical processes.
ASD includes a broad spectrum of symptoms. So, a single, brief evaluation can't tell a child's true abilities. It's best to have a team of specialists to evaluate the child. They might evaluate:
- Motor skills
- Success at school
- Thinking abilities
Some parents don't want to have their child diagnosed because they're afraid the child will be labeled. But without a diagnosis, their child may not get the needed treatment and services.
At this time, there is no cure for ASD. A treatment program will greatly improve the outlook for most young children. Most programs build on the interests of the child in a highly structured schedule of constructive activities.
Treatment plans may combine techniques, including:
- Applied behavior analysis (ABA)
- Medicines, if needed
- Occupational therapy
- Physical therapy
- Speech-language therapy
APPLIED BEHAVIORAL ANALYSIS (ABA)
This program is for younger children. It helps in some cases. ABA uses one-on-one teaching that reinforces various skills. The goal is to get the child close to normal functioning for their age.
An ABA program is often done in a child's home. A behavioral psychologist oversees the program. ABA programs can be very expensive and aren't widely used by school systems. Parents often have to find funding and staffing from other sources, which aren't available in many communities.
Another program is called the Treatment and Education of Autistic and Related Communication Handicapped Children (TEACCH). It uses picture schedules and other visual cues. These help children work on their own and organize and structure their environments.
Though TEACCH tries to improve a child's skills and ability to adapt, it also accepts the problems associated with ASD. Unlike ABA programs, TEACCH doesn't expect children to achieve typical development with treatment.
There is no medicine that treats ASD itself. But medicines are often used to treat behavior or emotional problems that people with ASD may have. These include:
- Attention problems
- Extreme compulsions that the child cannot stop
- Mood swings
- Sleep difficulty
Only the drug risperidone is approved to treat children ages 5 through 16 for the irritability and aggression that can occur with ASD. Other medicines that may also be used are mood stabilizers and stimulants.
Some children with ASD seem to do well on a gluten-free or casein-free diet. Gluten is in foods containing wheat, rye, and barley. Casein is in milk, cheese, and other dairy products. Not all experts agree that changes in diet make a difference. And not all studies have shown positive results.
If you're thinking about these or other diet changes, talk to both a provider and a registered dietitian. You want to be sure that your child is still getting enough calories and the right nutrients.
Beware of widely publicized treatments for ASD that don't have scientific support, and reports of miracle cures. If your child has ASD, talk with other parents. Also discuss your concerns with ASD specialists. Follow the progress of ASD research, which is rapidly developing.
Many organizations provide additional information and help on ASD.
With the right treatment, many ASD symptoms can be improved. Most people with ASD have some symptoms throughout their lives. But, they're able to live with their families or in the community.
When to Contact a Medical Professional
Parents usually suspect that there is a developmental problem long before a diagnosis is made. Call your provider if you think that your child is not developing normally.
Bridgemohan CF. Autism spectrum disorder. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 54.
Centers for Disease Control and Prevention website. Autism spectrum disorder (ASD): recommendations and guidelines.
National Institute of Mental Health website. Autism spectrum disorder.
Sidhu R, O'Banion DD, Hall C. Autism and other developmental disabilities. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 90.
Last reviewed on: 6/7/2022
Reviewed by: Neil K. Kaneshiro, MD, MHA, Clinical Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.