Adobe PDFAutism Spectrum Disorders

What is Autism?

According to the Diagnostic and Statistical Manual (DSM-5)  autism spectrum disorder (ASD) is classified as a developmental disorder, with or without intellectual disability (ID), which is characterized by impairment(s) in reciprocal social communication and social interaction (i.e. turn taking activities, such as a two person conversation) and restricted, repetitive patterns of behavior, interests or activities (i.e. an individual who talks exclusively about trains). These characteristics are typically present from early childhood and may limit or impair everyday functioning. Today, the CDC estimates that roughly 1 in 68 children in the United States have ASDs.   Boys are five times more likely to have ASDs as compared to girls. 

What Are the Different Types of Autism Spectrum Disorders (ASD)?

According to the CDC, there are three different types of ASDs:

  • Autism Spectrum Disorder (also called “classic” autism) - This is what most people think of when hearing the word “autism.” People with autism usually have significant language delays, social and communication challenges, and behaviors and interests different from those without autism. Many people with autism also have intellectual disability.
  • Asperger Syndrome - People with Asperger syndrome usually function at the higher lever of the autism spectrum. They might have social challenges and different behaviors and interests. However, they typically do not have problems with language or have intellectual disability.
  • Pervasive Developmental Disorder – Not Otherwise Specified (PDD-NOS; also called “atypical autism”) - People who meet some of the criteria for autism or Asperger syndrome, but not all, may be diagnosed with PDD-NOS. People with PDD-NOS usually have fewer behaviors than those with autism. The behaviors might cause only social and communication challenges. (

How Many People Have ASDs?

More people than ever before are being diagnosed with autism. But, it is not clear whether this is due to the creation of a broader definition of what ASDs are or possibly better efforts in diagnosing the condition. Regardless, a true increase of autism cannot be ruled out. CDC estimates that roughly 1 in 80 and 1 in 240 (with an average of 1 in 110) children in the United States have ASDs. This makes ASDs more common than childhood cancer, juvenile diabetes and pediatric AIDS combined. An estimated 1.5 million people in the U.S. and tens of millions worldwide are affected by ASDs.

Who Is Most Often Affected?

While ASDs occur in all racial, ethnic and socioeconomic groups, boys are four times more likely to have ASDs compared to girls. Current estimates in the United States find that one out of 70 boys is diagnosed with autism. Three groups of people seem to be at higher risk:

  • Boys
  • Siblings of those with autism
  • People with certain other developmental disorders, such as Fragile X syndrome

What Signs Should Parents Be Aware Of?

Signs may not be noticeable until around the ages of two to six years old. The National Institute of Child Health and Human Development (NICHD) provide five behaviors that warrant the need for further evaluation. The child:

  • Does not babble or coo by 12 months
  • Does not gesture (point, wave, grasp) by 12 months
  • Does not say single words by 16 months
  • Does not say two-word phrases on his or her own by 24 months
  • Has any loss of any language or social skill at any age

The presence of these signs does not prove that a child has autism. But, it does mean the child should be evaluated further by a team consisting of a neurologist, psychologist, developmental pediatrician, speech/language therapist, learning consultant, or other professionals knowledgeable about autism.

How Are ASDs Diagnosed?

Diagnosing ASDs can be a challenge since there is no medical test (like a blood test) to verify the disorder exists. Doctors consider the child’s behavior and development to make a diagnosis. An ASD diagnosis is considered reliable by age 2, although most do not receive a final diagnosis until they are much older. Two steps are taken to diagnose ASDs:

  1. Developmental Screening: This is a short test to determine if the child is learning basic skills at the age they should be learning them. A delay in any area could be a sign there is a problem. Children should be screened specifically for ASDs during regular well-child doctor visits at 18 and 24 months, with additional screening if a child is at high risk for ASDs or if behaviors associated with ASDs are present.
  2. Comprehensive Diagnostic Evaluation: The second step is obtaining a comprehensive evaluation that may include looking at the child’s behavior and development and interviewing the parents. Hearing and vision screening, genetic testing, neurological testing, and other medical testing are often conducted as well. The primary care doctor may choose to refer the child to a specialist for further testing, such specialists include developmental pediatricians, child neurologists and child psychologists or psychiatrists.

How Does The Arc Help People with ASDs and Their Families?


People with ASDs and the family members who care about them need support in many ways. Families need help navigating and getting the support they need.

The Arc has over 650 state and local chapters that serve people with various intellectual and developmental disabilities, including autism. The Arc’s Autism Now: The National Autism Resource and Information Center is a dynamic and interactive lifeline of resources and information for families in need. 

For more information, visit The Arc at and The Arc’s Autism Now Center at


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January 27, 2012