Autism is difficult to diagnosis. When the diagnosis is made, it can be heartbreaking to parents. Denial is the first response, and it may go on for so long that appropriate treatment is delayed, sometimes to the detriment of the child.

Parents are usually the first to suspect something is wrong. A previously normal child will suddenly act odd. Language development may stop or regress; social reactions may become inappropriate or disappear altogether. Or, bizarre behavior may appear, such as tantrums or obsessive repetition. Such ]]>symptoms]]> should be mentioned at routine doctor visits, where they will be explored to determine if they warrant referral to a specialist.

Professionals who specialize in autism—child psychiatrists, child psychologists, developmental pediatricians, and pediatric neurologists—will observe the child's behavior, social contacts, and communication skills. They will assess mental and social skills and develop a detailed history of the child's behavior. Some doctors ask parents to bring in videotapes of the child at home. Photo albums and other records may help in identifying time sequences.

If autism is suspected, other tests may include:

  • Psychological tests
  • IQ tests
  • Medical tests to investigate other related conditions. These tests may include the following:

Psychological Tests

A variety of age-appropriate questionnaires and skill tests compare a child's abilities and responses to standards established by testing thousands of "normal" children. Some test motor skills, like stacking blocks. Some test visual and coordination skills. Some compare daily activities with others of the same age.

IQ Tests

These are comparative evaluations of individuals at the same age with respect to age-appropriate intellectual skills, like pattern recognition and problem solving. An IQ is the ratio of the child's calendar age to his intellectual "age"—the average performance of others at a given age. For example, if a 5-year-old child performs like a 10-year old, his IQ would be 200.

Blood and Urine Tests

Thousands of tests evaluate physical health. Some are done routinely, like a blood count and urinalysis. Others types of blood and urine tests are done only rarely for unusual conditions. Your doctor will select all that are appropriate.

DNA and Chromosome Testing

Genetic disorders are detected by looking at your genes. Certain genetic disorders are associated with autism, like tuberous sclerosis and ]]>fragile X syndrome]]> .

Electroencephalogram (EEG)

This is a test that records the brain's activity by measuring electrical currents through the brain. Abnormalities may indicate a ]]>seizure disorder]]> , which is commonly associated with autism.