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Autism Spectrum Disorders

(Autism; ASD)


Autism spectrum disorders (ASD) are a range of complex brain disorders. The disorders result in social, behavioral, and communication problems. Asperger syndrome and pervasive developmental disorders used to be known as separate conditions but are now considered part of ASD.


ASD is a neurodevelopmental disorder. This means that problems in brain development cause ASD. Scientists are searching for answers about what causes these development problems. Studies suggest:

  • ASD seems to run in some families. Several genes may be involved.
  • Problems during pregnancy or delivery may interfere with normal brain development.
  • Something in the environment that a child is exposed to may be a factor.
  • Problems or exposures during pregnancy

Risk Factors

ASD is more common in boys. Other factors that increase the chance of ASD include:

  • Family history—siblings of a child with ASD are at higher risk
  • Having parents who are older
  • Problems during pregnancy or delivery
  • Mother with rubella during pregnancy
  • Epilepsy —especially when diagnosed under age 2 years
  • A number of other conditions are related to ASD, although the relationship between them is not clear:
The Conditions Above Primarily Affect the Central Nervous System
Central Nervous System

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ASD usually first appears during early childhood between 2-6 years old. The severity of symptoms varies. Behaviors and abilities may differ from day to day. Symptoms may decrease as the child grows older. Children with ASD may have a combination of abnormal behaviors.

Symptoms include:

  • Avoiding social contact
  • Having problems with language such as loss of language
  • Using words incorrectly
  • Communicating with motions instead of words
  • Avoiding eye contact
  • Having trouble with nonverbal communication
  • Lacking interest in normal activities for that age
  • Spending a lot of time alone
  • Not playing imaginatively
  • Not starting pretend games
  • Not imitating others
  • Having sensitivity to sound, smell, taste, sights, and touch
  • Reacting to stimulation in an abnormal way
  • Not reacting to smiles
  • Delayed motor skill development
  • Being hyperactive
  • Being passive
  • Having tantrums
  • Being single-minded
  • Being aggressive
  • Hurting self
  • Repetitive movement, such as rocking or flapping a hand
  • Resisting change
  • Forming unusual attachments to objects
  • Sniffing or licking of toys
  • Not understanding other peoples' feelings and needs
  • Being a picky eater
  • Having gastrointestinal problems, such as diarrhea, constipation, or frequent abdominal pain

Some people with ASD suffer from other disorders as well, including:


Doctors who specialize in ASD will observe the child's behavior, social contacts, and communication abilities. They will evaluate mental and social development. Parents will be asked about their child's behavior. Some doctors ask parents to bring in videos of the child at home.

Tests may include:

  • Neuropsychological tests
  • Questionnaires and observation schedules
  • Intelligence tests

Medical tests to rule out other conditions that cause similar symptoms may include:

  • Blood tests
  • Urine tests
  • DNA testing

An electroencephalogram (EEG) may also be done to record brain activity.


There is no cure for ASD. The severity of symptoms may decrease over the years. Children with ASD and their families may benefit from early intervention. Children aged 18-30 months who had high-intensity intervention showed improvements in their IQ, language, and behavior.

Children with ASD respond well to a structured, expected schedule. Many children with ASD learn to cope with their disabilities. Most need assistance and support throughout their lives. Others are able to work and live independently when they grow up.

Children with ASD can benefit from:

Special Education

Programs that meet the child's special needs improve the odds of learning. Children with ASD may have trouble with assignments, concentration, and anxiety. Teachers who understand the condition can work with the child's abilities. Programs should use the child's interests. Some children do better in a small-group setting. Others do well in regular classrooms with special support. Vocational training can help prepare young adults for a job.

Therapy Services

Speech, physical, and occupational therapies may improve speech and activities. Children with ASD need help developing social skills. Mental health professionals can help a family cope with caring for a child with ASD. Counselors help parents learn how to manage behaviors.

Applied Behavioral Analysis

ABA is a type of behavior program. It can be used in school, in a therapy setting, and at home. There are a number of different kinds of ABA programs. Talk to your child's doctor about which one might be helpful for your child.


There are no drugs to treat ASD. Some drugs are used to help manage symptoms. Medications for anxiety and depression can also help treat obsessive and aggressive behaviors. Your child's doctor may use other medications to help control other disruptive behaviors.

Other Therapies

There are other treatments available. These include dietary changes and alternative therapies. Talk with your child's doctor first to see if any of these would be helpful for your child.


There are no current guidelines to prevent ASD because the cause is unknown.


The Autism Society

Centers for Disease Control and Prevention


Autism Canada Foundation

Health Canada


Autism spectrum disorder fact sheet. National Institute of Neurological Disorders and Stroke website. Available at: Updated December 6, 2017. Accessed March 19, 2018.

Autism spectrum disorder. National Institute of Mental Health website. Available at: Updated October 2016. Accessed March 19, 2018.

Autism spectrum disorders. EBSCO DynaMed Plus website. Available at: Updated February 2, 2018. Accessed March 19, 2018.

Autism spectrum disorders (ASDs). Centers for Disease Control and Prevention website. Available at: Updated December 6, 2017. Accessed March 19, 2018.

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Last reviewed March 2018 by EBSCO Medical Review Board Kari Kassir, MD  Last Updated: 1/26/2018