Learn About Autism Spectrum Disorder

What is the definition of Autism Spectrum 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.

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What are the alternative names for Autism Spectrum Disorder?

Autism; Autistic disorder; Asperger syndrome; Childhood disintegrative disorder; Pervasive developmental disorder

What are the causes of Autism Spectrum Disorder?

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:

  • Autistic disorder
  • Asperger syndrome
  • Childhood disintegrative disorder
  • Pervasive developmental disorder
What are the symptoms of Autism Spectrum Disorder?

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 problems 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
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What are the current treatments for Autism Spectrum Disorder?

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


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:

  • Aggression
  • Anxiety
  • Attention problems
  • Extreme compulsions that the child cannot stop
  • Hyperactivity
  • Impulsiveness
  • Irritability
  • Mood swings
  • Outbursts
  • Sleep difficulty
  • Tantrums

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.

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What are the support groups for Autism Spectrum Disorder?

Many organizations provide additional information and help on ASD.

What is the outlook (prognosis) for Autism Spectrum Disorder?

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.

What are the possible complications of Autism Spectrum Disorder?

ASD can be linked with other brain disorders, such as:

  • Fragile X syndrome
  • Intellectual disability
  • Tuberous sclerosis

Some people with autism develop seizures.

The stress of dealing with autism can lead to social and emotional problems for families and caregivers, and for the person with autism.

When should I contact a medical professional for Autism Spectrum Disorder?

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.

What are the latest Autism Spectrum Disorder Clinical Trials?
The Effect of a Combination of Human Milk Oligosaccharides (HMOs) and Probiotics on Behavioural Change in Children With Autism Spectrum Disorder (ASD).

Summary: This research project will investigate if a supplement containing a unique combination of prebiotics and probiotics can influence behaviour in children diagnosed with autism spectrum disorder. The study will use a combination of human milk oligosaccharides (HMOs, prebiotics) and probiotics as an oral powder.This clinical trial will have two consecutive phases. Phase 1A is an 8-week randomised, dou...

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Familial and Functional Study of Genetic Variants Identified in People With Schizophrenia, Bipolar Disorder, Autism Spectrum Disorder or Resistant Depression

Summary: Genetic analyses conducted on patient with psychiatric disorders assessed at the expert centres resulted in the identific action of genetic variants associated with psychiatric disorders (Courtois, 2020). These data require further genetic and functional analyses. The first objective of this study is to investigate the disease-related inheritance of genetic variants in the families of individuals ...

What are the Latest Advances for Autism Spectrum Disorder?
Analysis of Neurodevelopment in Children Born Extremely Preterm Treated With Acid Suppressants Before Age 2 Years.
Therapeutic applications of transcutaneous auricular vagus nerve stimulation with potential for application in neurodevelopmental or other pediatric disorders.
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Hyperbaric oxygen therapy in children with post-concussion syndrome improves cognitive and behavioral function: a randomized controlled trial.
Who are the sources who wrote this article ?

Published Date: June 07, 2022
Published 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.

What are the references for this article ?

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. www.cdc.gov/ncbddd/autism/hcp-recommendations.html. Updated April 7, 2022. Accessed July 18, 2022.

National Institute of Mental Health website. Autism spectrum disorder. www.nimh.nih.gov/health/topics/autism-spectrum-disorders-asd. Updated March 2022. Accessed July 18, 2022.

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.