Autism is a pervasive developmental disorder, meaning that it affects how a child functions in several areas, including speech, social skills and behavior. Children who have problems in these areas are sometimes said to have an autistic spectrum disorder because the severity of symptoms varies greatly.
Autism affects about 2 to 6 children per 1,000 in the U.S. The number of affected children appears to be rising. The rates of autism are about four times higher than 30 years ago. The causes of this apparent increase are not known. Improved awareness and changes in how autism is diagnosed may explain much if not all of the increase.
Symptoms of Autism
Children with autism have a number of symptoms, ranging from mild to severe. Symptoms include:
- Difficulties interacting with others and making friends
- Communication problems, both with spoken language and nonverbal gestures
- Insistence on sameness
- Repetitive movements, such as hand flapping or frequent tantrums
- Some degree of mental retardation or learning disabilities in most (but by no means all) of affected children
Children with a mild autistic spectrum disorder called Asperger syndrome share some of the features of autism, though children with Asperger syndrome have normal intelligence and learn to speak at the expected age.
When Is Autism Diagnosed?
A child with autism usually does not look different from other children. He or she may appear to develop normally for the first year or so of life. But during the second year of life a child may begin to fall behind in social skills, fail to develop speech or even lose skills that had been previously acquired. Autism is usually diagnosed by the time a child is about 3 years of age.
How Is Autism Diagnosed?
There is no medical test to diagnose autism. Doctors usually diagnose autism by observing a child's behavior. Sometimes they use screening tests that measure a number of characteristics and behaviors associated with autism.
Who Is at Risk?
Autism occurs in all racial, social and educational groups. Boys are 3 to 4 times as likely as girls to be affected. Siblings of an affected child may be at increased risk of autism, though the risk appears fairly low (2 to 8 percent).
Causes of Autism
While the causes of autism are poorly understood, scientists do know that autism is not caused by poor parenting or other social factors. It is a biological disorder that appears to be associated with subtle developmental abnormalities in specific structures or functions in the brain.
Studies suggest that in most cases, multiple genes contribute to the disorder. Researchers have identified about 10 genes that appear to play a role in autism. These genes appear only to contribute to autism. They may not cause the disorder. In a small minority of cases, other genetic diseases (such as fragile X syndrome) and infections occurring before birth (such as rubella and cytomegalovirus) also may play a role.
Do Childhood Vaccines Contribute to Autism?
Childhood vaccines, including the measles/mumps/rubella vaccine, do not cause autism. Some parents of children with autism suspect that this vaccine, given around 15 months of age, contributes to autism because children sometimes begin to display symptoms of autism around the time they were vaccinated. Most likely, this is the age when symptoms of the disorder commonly begin, even if a child is not vaccinated.
Another reason that childhood vaccines were suspected of playing a role in autism is that, until recently, they contained a preservative called thimerosal that contains mercury. (Since 2002, all routine childhood vaccines have been free of thimerosol. The exception is the flu shot, and thimerosol-free versions are available.) While higher doses of certain forms of mercury may affect brain development, studies suggest that thimerosal does not. In 2004, an Institute of Medicine panel concluded, after reviewing many studies, that there is no convincing evidence of any link between autism and the measles, mumps, rubella (MMR) vaccine or thimerosol-containing vaccines.
Children often show great improvement in symptoms with intensive behavioral treatment beginning during the preschool years. An individualized treatment program can begin as early as age 2 or 3 and continue through the school years.
There is no cure for autism. However, some children benefit from medications that help improve their behavioral symptoms so that they are better able to learn. Some commonly used medications include antidepressants, anti-psychotics and stimulants. One such medication is Ritalin, which is commonly prescribed for attention deficit hyperactivity disorder (ADHD).
Some studies also suggest that nutritional therapy, including supplementation with certain vitamins (such as B vitamins), may improve symptoms in some children. Families should always consult their child's physician before beginning any nutritional therapy.
Common Characteristics of Autism
Each child with autism is unique, but some common characteristics and behaviors may include:
- Does not speak
- Repeats words
- Has difficulty starting or maintaining conversation
- Does not respond to being called by name
- Focuses on a single subject or activity
- Is overly sensitive to touch or sound
- Dislikes being held or cuddled
- Lacks facial expression or doesn't make eye contact
- Has sleep disturbances
- Insists on same routine
- Lacks fear in risky situations
For More Information
Autism Society of America (800)-3AUTISM
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