Print Friendly and PDF
► Health Information LibraryHealth TopicsBehavioral and EmotionalAutism spectrum disorder

Autism spectrum disorder


Autism spectrum disorder (ASD) is a developmental disorder that appears in the first 3 years of life. ASD affects the brain's normal development of social and communication skills.

Alternative Names

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


Autism spectrum disorder (ASD) is a physical condition linked to abnormal biology and chemistry in the brain. The exact causes of these abnormalities are not known. There is likely a combination of factors that lead to ASD. It may run in some families, and research shows that a number of genes may be involved.

Many other possible causes have been suspected, but not proven. Some researchers believe that damage to a specific part of the brain, called the amygdala, may be involved. Other researchers are looking at whether a virus may trigger symptoms.

Some parents have heard that vaccines children receive may cause ASD. Several research studies have found no connection between vaccines and ASD. The American Academy of Pediatrics and the Centers for Disease Control and Prevention report that there is no link between ASD and vaccines.

Some doctors think the increase in the number of children with ASD is due to better diagnosis and newer definitions of ASD. The term autism spectrum disorder now includes conditions that used to be diagnosed separately:

  • Autistic disorder
  • Asperger syndrome
  • Childhood disintegrative disorder
  • Pervasive developmental disorder


Most parents of ASD children suspect that something is wrong by the time the child is 18 months old and seek help by the time the child is age 2. Children with ASD typically have problems in:

  • Pretend play
  • Social interactions
  • Verbal and nonverbal communication

Some children seem normal before age 1 or 2 and then suddenly regress and lose language or social skills they had previously gained.

Symptoms can vary from moderate to severe.

A person with autism may:

  • Be overly sensitive in sight, hearing, touch, smell, or taste (for example, they may refuse to wear "itchy" clothes and become distressed if they are forced to wear the clothes)
  • Be very distressed when routines are changed
  • Perform repeated body movements
  • Show unusual attachments to objects

Communication problems may include:

  • Cannot start or maintain a social conversation
  • Communicates with gestures instead of words
  • Develops language slowly or not at all
  • Does not adjust gaze to look at objects that others are looking at
  • Does not refer to self correctly (for example, says "you want water" when the child means "I want water")
  • Does not point to direct others' attention to objects (normally occurs in the first 14 months of life)
  • Repeats words or memorized passages, such as commercials

Social interaction:

  • Does not make friends
  • Does not play interactive games
  • Is withdrawn
  • May not respond to eye contact or smiles, or may avoid eye contact
  • May treat others as if they are objects
  • Prefers to spend time alone, rather than with others
  • Shows a lack of empathy

Response to sensory information:

  •  Does not startle at loud noises
  • Has heightened or low senses of sight, hearing, touch, smell, or taste
  • May find normal noises painful and hold hands over ears
  • May withdraw from physical contact because it is overstimulating or overwhelming
  • Rubs surfaces, mouths or licks objects
  • Seems to have a heightened or low response to pain


  • Does not imitate the actions of others
  • Prefers solitary or ritualistic play
  • Shows little pretend or imaginative play


  • Acts up 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
  • Shows aggression to others or self
  • Shows a strong need for sameness
  • Uses repetitive body movements

Exams and Tests

All children should have routine developmental exams done by their pediatrician. Further testing may be needed if the doctor or parents are concerned. This is particularly true if a child fails to meet any of the following 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 receive a hearing evaluation, blood lead test, and screening test for ASD.

A health care provider experienced in diagnosing and treating ASD is usually needed to make the actual diagnosis. Because there is no biological test, such as a blood test, for ASD, the diagnosis will often be based on guidelines from a medical book called the Diagnostic and Statistical Manual of Mental Disorders (DSM-V).

An evaluation of ASD will often include a complete physical and nervous system (neurologic) examination. Tests may be done to see if there is a problem with genes or the body's metabolism.

ASD includes a broad spectrum of symptoms. Therefore, a single, brief evaluation cannot predict a child's true abilities. It is best to have a team of specialists evaluate the child. They might evaluate:

  • Communication
  • Language
  • Motor skills
  • Speech
  • Success at school
  • Thinking abilities

Some parents do not want to have their child diagnosed because they are afraid the child will be labeled. But without a diagnosis, the child may not get the necessary treatment and services.


At this time, there is no cure for ASD. An early, intensive, appropriate treatment program will greatly improve the outlook for most young children with ASD. Most programs build on the interests of the child in a highly structured schedule of constructive activities.

The best treatment plan may use a combination of techniques, including:

  • Applied behavior analysis (ABA)
  • Medications
  • Occupational therapy
  • Physical therapy
  • Speech-language therapy


This program is for younger children. It can be effective in some cases. ABA uses one-on-one teaching that reinforces the practice of various skills. The goal is to get the child close to normal developmental functioning.

ABA programs are usually done in a child's home under the supervision of a behavioral psychologist. These programs can be very expensive and have not been widely adopted by school systems. Parents often must seek funding and staffing from other sources, which can be hard to find in many communities.


Another program is called the Treatment and Education of Autistic and Related Communication Handicapped Children (TEACCH). TEACCH was developed as a statewide program in North Carolina. It uses picture schedules and other visual cues that help the child work independently and organize and structure their environments.

Though TEACCH tries to improve a child's adaptation and skills, it also accepts the problems associated with ASD. Unlike ABA programs, TEACCH programs do not 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, including:

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

Currently, only 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 include mood stabilizers and stimulants.


Some children with ASD appear to respond to a gluten-free or casein-free diet. Gluten is found in foods containing wheat, rye, and barley. Casein is found in milk, cheese, and other dairy products. Not all experts agree that dietary changes will make a difference, and not all studies of this method have shown positive results.

If you are considering these or other dietary changes, talk to both a doctor who specializes in the digestive system (gastroenterologist) and a registered dietitian. You want to be sure that the child is still receiving enough calories, nutrients, and a balanced diet.


Beware that there are widely publicized treatments for ASD that do not have scientific support, and reports of miracle cures that do not live up to expectations. If your child has ASD, it may be helpful to talk with other parents of children with ASD and ASD specialists. Follow the progress of research in this area, which is rapidly developing.

Support Groups

Many organizations provide additional information and help on ASD.

Outlook (Prognosis)

With the right therapy, many ASD symptoms can be improved. Most people with ASD continue to have some symptoms throughout their lives, though they are able to live with their families or in the community.

Possible Complications

ASD can be associated with other disorders that affect the brain, such as:

Some people with autism develop seizures.

The stresses of dealing with autism can lead to social and emotional complications for families and caregivers, as well as for the person with autism.

When to Contact a Medical Professional

Parents usually suspect that there is a developmental problem long before a diagnosis is made. Call your health care provider if you think that your child is not developing normally.


American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 5th ed. Arlington, VA: American Psychiatric Publishing. 2013. 

Centers for Disease Control and Prevention and American Academy of Pediatrics. Autism A.L.A.R.M. 2012. Available at Accessed May 9, 2014.

Nass R, Ross G. Developmental disabilities. In: Daroff RB, Fenichel GM, Jankovic J, Mazziotta JC, eds. Bradley's Neurology in Clinical Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 61.

Nazeer A, Ghaziuddin M. Autism spectrum disorders: clinical features and diagnosis. Pediatr Clin N Am. 2012;59:19-25.

Raviola G, Gosselin GJ, Walter HJ, DeMaso DR. Pervasive developmental disorders and childhood psychosis. In: Kliegman RM, Stanton BF, St. Geme JW III, et al., eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 28.