What Is Autism Spectrum Disorder (ASD)?

Autism Spectrum Disorder (ASD) is a complex, lifelong developmental disability that can cause significant social, communication, self-regulation, and behavioral challenges. Autism is referred to as a spectrum disorder – meaning the symptoms can occur in any combination and with varying degrees of severity. The Autism experience is different for everyone. The characteristic behaviors of ASD may or may not be apparent in infancy, but usually becomes obvious during early childhood (24 months to 6 years). ASD affects individuals in every country and region of the world and knows no racial, ethnic, nor economic boundaries.

While there is currently no known single cause of Autism, early diagnosis helps a person receive resources that can support the choices and opportunities needed to live fully.


What Is Autism

Overview of Autism

Autism is a developmental disorder of neurological origin that affects, often severely, a person’s ability to communicate and socially interact with others. The diagnosis is four times more prevalent in males than females.

Autism is considered a spectrum disorder because the number and intensity of the symptoms people with autism display may vary widely. However, all people with Autism demonstrate impairments in the following three areas: communication, social relationships, and restricted patterns of behavior.

Contrary to popular understanding, many children and adults with Autism may make eye contact, show affection, smile and laugh, and demonstrate a variety of other emotions, although in varying degrees. The symptoms and characteristics of Autism can present themselves in a wide variety of combinations, from mild to severe. Although Autism is defined by a certain set of behaviors, children and adults can exhibit any combination of the behaviors in any degree of severity. Two children, both with the same diagnosis can act very differently from one another and have varying skills.


When family members or support providers become concerned that a child is not following a typical developmental course, they turn to experts, including psychologists, educators and medical professionals, for a diagnosis.

At first glance, some people with Autism may appear to have an intellectual disability, sensory processing issues, or problems with hearing or vision, and the diagnosis of Autism may become more challenging.

These conditions can co-occur with Autism and it can be confusing to families when they receive multiple diagnoses. However, it is important to identify Autism, as an accurate and early Autism diagnosis can provide the basis for appropriate educational and home-based support.

There are many differences between a medical diagnosis and an educational determination, or school evaluation, of a disability.

Medical Diagnosis

A medical diagnosis is made by a psychologist, developmental pediatrician, or other specialized physician based on an assessment of symptoms and diagnostic tests. A medical diagnosis of Autism spectrum disorder is most frequently made according to the Diagnostic and Statistical Manual (DSM-5, released 2013) of the American Psychiatric Association. This manual guides physicians in diagnosing Autism spectrum disorder according to a specific set of criterion.

A brief observation in a single setting cannot present a true picture of someone’s abilities and behaviors. The person’s developmental history and input from parents, caregivers and/or teachers are important components of an accurate diagnosis.

There are no medical tests, such as blood work or brain scans, for diagnosing Autism. An accurate medical diagnosis must be based on observation of the individual’s communication, social interaction, and their activities and interests.

Educational Determination

An educational determination is made by a multidisciplinary evaluation team of various school professionals. The evaluation results are reviewed by a team of qualified professionals and the parents to determine whether a student qualifies for special education and related services under the Individuals with Disabilities Education Act (IDEA) (Hawkins, 2009).

An educational determination can qualify an individual for support within school settings. However, an educational determination is not the same as a medical diagnosis, and often will not qualify an individual for therapies and support outside of school that would typically be covered by insurance or Medicaid. Additionally, a medical diagnosis of Autism does not guarantee an educational determination.


Early identification is associated with dramatically better outcomes for people with Autism. The earlier a child is diagnosed, the earlier they can begin benefiting from early intervention therapies and education.

The Centers for Disease Control and Prevention’s National Center on Birth Defects and Developmental Disabilities (NCBDD) recommends that all children be screened for Autism by their family pediatrician three times by the age of three – at nine, 18, and 24 or 30 months. Intervention should start when an Autism diagnosis is suspected, rather than when a formal diagnosis is made.

The advantages of early intervention cannot be overemphasized. Children who receive early intervention can make tremendous strides in their overall skill development, leading to improved quality of life.

The CDC provides a wealth of information on the early signs of Autism through its “Learn the Signs. Act Early” initiative.

While there is no one behavioral or communication assessment that can detect Autism, several screening instruments have been developed for use in determining if a child might need further evaluation for developmental delay and/or Autism, including the Ages and Stages Questionnaire (ASQ) and the Modified Checklist for Autism in Toddlers (M-CHAT). For detailed information about these instruments and the research behind them, click here.


1 https://agesandstages.com/

2 https://mchatscreen.com/

3 https://publications.aap.org/pediatrics/article/141/6/e20180965/37695/Improving-Screening-for-Autism-Spectrum-Disorder?autologincheck=redirected?nfToken=00000000-0000-0000-0000-000000000000

While there is not a single behavioral or communication test that can detect Autism, several Autism-specific tools are now being used for formal diagnosis. These include the Autism Diagnostic Observation Schedule, Second Edition (ADOS™-2), the Autism Diagnostic Interview (ADI), the Screening Tool for Autism in Toddlers (STAT), the Childhood Autism Rating Scales (CARS), and the Tele-ASD-Peds for diagnosis for use in telehealth. All of these tests should be used as part of a larger assessment, and not just on their own, as the determination of Autism is best completed with multiple sources of information.

What Are The Signs

Individuals with ASD often have problems with social, emotional, and communication skills. They might repeat certain behaviors and might not want change in their daily activities. Many individuals with ASD also have different ways of processing, learning, paying attention, or reacting to things. In some cases, aggressive and/or self-injurious behavior may be present. Persons with autism may also exhibit some of the following traits:

  • Insistence on sameness; resistance to change
  • Difficulty in expressing needs; using gestures or pointing instead of words
  • Repeating words or phrases in place of normal, responsive language
  • Prefers to be alone, aloof manner
  • Difficulty mixing with others
  • Unresponsive to typical teaching methods
  • Noticeable over-sensitivity or under-sensitivity to pain
  • No real fear of danger
  • Uneven gross/fine motor skills
  • Not responsive to verbal cues; acts as if deaf, although hearing test in the normal range


Autism is prevalent across the world, although tracking rates can vary due to differences in reporting. In 2021, the Centers for Disease Control and Prevention (CDC) issued its Autism prevalence report

  • The report concluded that the prevalence of Autism had risen to 1 in every 36 – more than twice as great as the 2004 rate of 1 in 125.
  • Children who receive an Autism diagnosis by age 4, are fifty times more likely to receive services.
  • The 2021 report noted that more White and Black children were identified with Autism than Hispanic children.
  • The 2020 report was the first to indicate that, on average, White and Black children were equally as likely to have a diagnosis by the age of 8 years, in the sample studied by the CDC.
  • Previous studies have shown, that children of color may still receive their diagnoses later than White children. Stigma, lack of access to healthcare services due to non-citizenship or low income, and non-English primary language are potential barriers to the early identification of Hispanic children and children of color with Autism.
  • Currently, boys are also approximately 4 times more likely to have an Autism diagnosis than girls of the same age.
  • However, recent research suggests that girls may not display characteristics of Autism in the same way as boys and might go undiagnosed because of their different presentation.
Next Steps


Autism Society promotes the active and informed involvement of family members and the individuals with autism in the planning of individualized, appropriate services and supports. The Next Step Guide was developed to help inform families of what is available for services and support. Autism Society NWPA will make every effort to keep the Next Step Guide updated. The guide (online) will be updated as information/services change.