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Autism Spectrum Disorder in Children

Autism spectrum disorder (ASD) is a developmental disability that can affect a child's social skills, communication and behavior. Because most children on the autism spectrum will sit, crawl and walk on time, you may not notice delays in social and communication skills right in the first year of life.

Looking back, many parents can recall early differences in interaction and communication. See What Are the Early Signs of Autism Spectrum Disorder?

Children on the autism spectrum and their families can be healthy and resilient

More research is needed to understand the course of development for children who are diagnosed on the autism spectrum. However, recent studies show that many children with an ASD diagnosis are healthy and doing well in mid-childhood.

How common is ASD?

About 1 in 36 U.S. children (2.8%) are diagnosed on the autism spectrum by the time they are 8 years old, according to 2020 data from the U.S. Centers for Disease Control and Prevention (CDC) Autism and Developmental Disabilities Monitoring Network​.

Boys are diagnosed on the spectrum nearly 4 times more often than girls. Still, for the first time, reported ASD diagnoses among 8-year-old girls has exceeded 1%. Also reported for the first time, the percentage of 8-year-old Black (2.9%), Hispanic (3.2%) and Asian or Pacific Islander (3.3%) children identified on the autism spectrum was higher than among 8-year-old White children (2.4%).

Overall, the number of children reported to be on the autism spectrum has increased since the early 1990s.

The increase could be caused by many factors. For example:

  • Many families became more aware of autism spectrum disorder.

  • Pediatricians began doing more screening for autism spectrum disorder, as recommended by the American Academy of Pediatrics. Children are identified earlier, which is a good thing.

  • Schools became more aware of ASD, and children began receiving more appropriate special education services.

  • There have been changes in how autism spectrum disorder is defined and diagnosed.

What causes ASD?

Children on the autism spectrum do not have one common cause or reason they have the condition. Many factors may lead to a diagnosis of autism spectrum disorder.

Scientists continue to learn more about what causes autism spectrum disorder. We currently know that:

  • Families do not cause autism spectrum disorder.

  • Vaccines do not cause autism spectrum disorder.

  • Family medical history may play a role. For a child diagnosed with autism spectrum disorder, the chance that a sibling might also be diagnosed is 10 to 20 times higher than for the general population. Relatives of children on the autism spectrum are more likely to share some similar social and behavioral characteristics of those seen among children with autism spectrum disorder. However, these characteristics may not be severe enough to be diagnosed.

  • Most children on the autism spectrum do not have a specific medical or genetic condition that explains why. However, autism spectrum disorder may occur more often in children with certain medical conditions or high-risk factors. These medical conditions can include fragile X syndrome, tuberous sclerosis complex, Down syndrome, or other genetic disorders. Infants born preterm are another high-risk group.

  • There are specific differences in brain function between a child on the autism spectrum and a child who is not on the autism spectrum.

  • Environmental factors that may contribute to autism spectrum disorder are also an important area of research; these are not yet well understood.

Changes in how autism is defined & diagnosed

Doctors use a book called Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) to assist in diagnosing autism spectrum disorder. In the past, only children with the most severe autism spectrum disorder symptoms were diagnosed. But in 2013, the diagnostic criteria for ASD changed. This was based on the research literature and clinical experience in the two decades since the DSM-IV was published in 1994. Now, children with more subtle characteristics are being identified as on the autism spectrum.

Several conditions used to be considered autism spectrum disorders in the DSM. Those conditions were:

  • Autistic disorder

  • Pervasive developmental disorder—not otherwise specified (PDD-NOS)

  • Asperger syndrome

  • Childhood disintegrative disorder

With publication of the fifth edition of the DSM in 2013, the terms listed above are no longer used and these conditions are now grouped in the broader category of autism spectrum disorder. Many people may self-identify as having Asperger Syndrome, but professionals should no longer use this terminology when making a diagnosis.

The benefits of early identification of autism

Early intervention

Each child on the autism spectrum has different needs. The sooner autism spectrum disorder is identified, the sooner an early intervention program directed at the child's symptoms can begin.

The AAP recommends that all children be screened for autism spectrum disorder at their 18- and 24-month well-child checkups. Research shows that starting an intervention program as soon as possible can improve outcomes for many children on the autism spectrum.

Co-existing conditions

In addition, children on the autism spectrum may have other medical problems that need further evaluation and treatment. Commonly co-existing conditions, called comorbidities, may include seizures, problems with sleep, gastrointestinal problems (feeding problems, abdominal pain, constipation, diarrhea) and behavioral health problems such as anxiety, ADHD, irritability and aggression.

Some of these medical conditions may place children on the autism spectrum at increased risk for more severe illness and complications from infections such as COVID-19.

How has COVID-19 affected autism screening?

Earlier in the COVID pandemic, parents may have been worried about the safety of taking their children to the pediatrician for well-child visits. CDC data suggests this impacted the frequency and timeliness of screening 4-year-olds for autism and other developmental delays.

Delays in well-child visits and autism screenings

Prior to March 2020, communities were evaluating and identifying more young children on the autism spectrum than they had in the past. After March 2020, that progress was wiped out. Disruptions in the timely evaluation of children, along with delays in connecting children to the services and support they need, could have long-lasting effects.

Disruptions in school services & supports

In addition, school, supports, activities and routines also were disrupted during to the pandemic. School closures and the absence of in-person interaction may have made it more difficult for teachers to recognize social and communication differences in their students. This may have meant more opportunities for early identification missed. Access to school services and therapies also became more difficult for many families because of the pandemic.


The pandemic has highlighted how, especially during times of change and uncertainty, it's important to stay connected. Remember to schedule your child's well-child visits with your pediatrician, especially if you have any concerns about your child's development or behavior. Talk to your pediatrician about the possibility of conducting these visits virtually if that is your preference.

You can reach out to peer support organizations, such as Family to Family Health Information Centers, for local information specific to children with special health care needs and disabilities.

More information

Last Updated
American Academy of Pediatrics (Copyright @ 2023)
The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.
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