Autism is a brain disorder that often interferes with a person's ability to communicate with and relate to others.

Signs of autism almost always develop before a child is 3 years old, although the condition is sometimes not diagnosed until later. Typically, parents first become concerned when they notice that their toddler does not begin to talk or does not respond and interact like other children of the same age. Toddlers with autism do not usually develop speech normally and may seem to be deaf although hearing tests are normal.

Autism also affects how a child perceives and processes sensory information.

The severity of autism varies. Some individuals need assistance in almost all aspects of their daily lives, while others are able to function at a very high level and can even attend school in a regular classroom. While this is a lifelong condition that typically results in some degree of social isolation, treatment can make a major difference in the lives of people with autism. Early diagnosis and comprehensive treatment has resulted in increasing numbers of people with autism being able to live independently as adults..

What causes autism?

Autism tends to run in families, suggesting a genetic link. Because people with autism can be vastly different, scientists suspect a number of genes are responsible. Ongoing research is targeted at pinpointing these genes. Some experts also believe that environmental factors may play a part in causing autism, although scientists have studied several factors, including vaccines, and have yet to identify such a cause.

Brain scans of people with autism have shown abnormalities in several areas of the brain, including those responsible for emotion and social relations. Other studies suggest that people with autism have high levels of the neurotransmitter serotonin, a chemical that sends messages in the brain. However, these findings are preliminary, and ongoing studies seek to explain the brain and autism.

What are the symptoms?

All people with autism have difficulty with social interactions and relationships. Parents often describe their child with autism as preferring to play alone and making little eye contact with other people. Other symptoms of autism include:

    * Difficulties with verbal and nonverbal communication. Language development in children with autism is almost always delayed.
    * Limited, repetitive, and overused (stereotyped) patterns of behavior, interests, and play. Many typical behaviors—such as repetitive body rocking, unusual attachments to objects, and holding fast to routines and rituals—are driven by the need for sameness and resistance to change.

There is no “typical” person with autism. Although autism is defined by the above characteristics, people with autism can have many different combinations of behaviors in mild to severe forms.

Do any other conditions occur with autism?

Although it is difficult to determine, studies show that below-normal intelligence occurs in about 70% of children with autism. 2 Teenagers with autism often become depressed and have increased anxiety, especially if they have average or above-average intelligence. In addition, about a third of children with autism develop a seizure disorder (such as epilepsy) by their teen years.

How is autism diagnosed?

Your health professional will use diagnostic guidelines, established by the American Academy of Child and Adolescent Psychiatry (AACAP), to determine whether your child has core symptoms. 4 A child may also have hearing and other tests to make sure developmental delays aren't the result of another condition with similar symptoms. Early diagnosis and treatment of autism is important to make the most of the child's potential.