Making a Diagnosis of Autism Spectrum Disorder - A Closer Look

What is the current estimated prevalence of ASD? What are the thoughts as to why it appears to be increasing?

Autism Prevalence
A little girl with her hands on her head

The most recent studies have reported current prevalence estimates in the United States to be approximately 1 in 59. This represents a twenty-fold increase from studies done 50 years ago.

Increased Prevalence

Great controversy has surrounded the so-called “autism epidemic” and whether or not the current rates reflect a true increase in incidence. Some factors believed to contribute to the increased rates include the following:

  • Greater awareness of autism in both the medical community and general public has led to increased screening and diagnosis.
  • American Academy of Pediatrics recommendations have led to increased screening.
  • Broadened definitions – Earlier studies predominantly included those with autistic disorder, while the more recent studies reflect the full spectrum.
  • Better Diagnostics – Children who had been diagnosed with other disorders (e.g., intellectual disability, language impairment) in the past are now being diagnosed as having an ASD (this applies to individual children who receive a new diagnosis and also reflects changing diagnostic patterns in the population over time).
  • Eligibility for services under the Individuals with Disabilities Education Act (IDEA) – In 1990, autism became a diagnosis for which children became eligible for special education services under the IDEA law.
  • There are likely unidentified factors associated with the increase in prevalence. Current epidemiologic studies, such as the Study to Explore Early Development (SEED), are looking at-risk and protective factors. See https://www.cdc.gov/ncbddd/autism/seed.html for more information.
  • Diagnosis of ASD in children with genetic syndromes that may have associated features of autism.

What evidence supports the major role of genetics in the etiology of ASD?

Little boys at the pumpkin patch

There is compelling evidence that autism has an underlying genetic etiology. It is considered to be a multi-factorial inherited disorder, with numerous twin studies estimating high heritability.

  • Recurrence risk for siblings is reported to be between 2% and 18%.  If a second child has autism, the recurrence risk for a subsequent (third) child is on the order of 25% to 35%.
  • ASD occurs four times more often in males than in females.

What would you do to support the patient and parents while awaiting an official diagnosis?

A caregiver playing with a child

Wait times between referral and diagnosis may vary. The process for Billy took six months. What would you do while parents are waiting for diagnosis results?

  • Maintain frequent contact with the family
  • Monitor early intervention services to advocate for appropriate intensity of services
  • Refer the family to parent support groups, such as Family Voices (www.familyvoices.orgexternal icon).