Definition

Autism is a spectrum of complex brain disorders. The disorders result in social, behavioral, and communication problems. Other conditions that are part of this spectrum include Asperger syndrome and pervasive developmental disorder.

Causes

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

• Autism 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.

Risk Factors

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

• Family history—siblings of a child with autism 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 autism, although the relationship between them is not clear:
  • Neurofibromatosis
  • Tuberous sclerosis
  • Fragile X syndrome
  • Phenylketonuria (PKU)
  • Möbius syndrome
  • Herpes encephalitis
  • Cytomegalovirus
  • Fetal alcohol syndrome
  • Angelman syndrome
  • Rett syndrome
  • Smith-Lemli-Opitz
  • Infantile spasms

Symptoms

Autism 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 autism 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 autism suffer from other disorders as well, including:

• Seizures
• Intellectual disability
• Genetic disorders, such as fragile X syndrome

Diagnosis

Doctors who specialize in autism will observe the child’s behavior, social contacts, and communication abilities. They will evaluate mental and social development. Parents will be asked about the 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.

Treatment

There is no cure for autism. The severity of symptoms may decrease over the years. Children with autism 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 autism respond well to a structured, expected schedule. Many children with autism 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 autism can benefit from:

Prevention

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

The Autism Society http://www.autism-society.org/

Autism Society Canada http://www.autismsocietycanada.ca

Autism fact sheet. National Institute of Neurological Disorders and Stroke website. Available at:
http://www.ninds.nih.gov/disorders/autism/detail_autism.htm
Updated May 7, 2013. Accessed May 14, 2013.

Autism spectrum disorder. National Institute of Mental Health website. Available at:
http://www.nimh.nih.gov/health/topics/autism-spectrum-disorders-asd/index.shtml
Updated May 14, 2013. Accessed May 14, 2013.

Autism spectrum disorders. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed
Updated May 6, 2013. Accessed May 14, 2013.

Autism spectrum disorders (ASDs). Centers for Disease Control and Prevention website. Available at:
http://www.cdc.gov/ncbddd/autism/index.html
Updated August 7, 2012. Accessed May 14, 2013.

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8/19/2014 DynaMed’s Systematic Literature Surveillance
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