What is Autism and Why Does it Matter to Me? Part 2: Characteristics and Prevalence of Autism

Welcome to the second post in my series on autism. This section is taken from a paper I wrote and is quite a bit more technical, so I have prefaced it with a summary. For the casual reader, the summary describes the contents fairly adequately. For the reader who wishes more details and citations, read the full content.

Summary: Autism Spectrum Disorder (ASD) is characterized by social and communication deficits, as well as repetitive behaviors and fixated interests (Parritz & Tory, 2014, p. 122). For a diagnosis of autism, we look for difficulties with social and emotional interactions, difficulty understanding and employing non-verbal communication, difficulty developing and maintaining relationships, repetitive behaviors, and fixated interests. Children with ASD also are more likely to have intellectual disability, ADHD, and anxiety disorders. Sometimes these co-existing disorders are more apparent to a parent than autism itself. 1 in 68 children are estimated to have autism. Boys are 4.5 times more likely to have autism than girls, but girls with autism are more likely to also have a diagnosis of intellectual disability. Autism is not something from which one can be “cured” because the neurological differences will be present throughout an individual’s lifetime. However, the behaviors and symptoms of autism may decrease in severity, especially with quality early intervention.


            Autism Spectrum Disorder (ASD) is characterized by social and communication deficits, as well as repetitive behaviors and fixated interests (Parritz & Tory, 2014, p. 122). The most recent Diagnostic and Statistics Manual (the standard for diagnosing childhood disabilities) outlines three social and communication deficits which must be present for the diagnosis of autism spectrum disorder in a child. These are deficits in “social– emotional reciprocity; deficits in nonverbal communication during social interactions; and deficits in developing and maintaining relationships” (Parritz & Troy, 2014, p. 123). In addition, children must display at least two types of repetitive behaviors and fixated interests (Parritz & Troy, 2014, p. 123). These can be movements, such as when Brett jumps up and down or claps his hands over his years. Brett’s obsession with trains is an example of a fixated interest. This category could also include repetitive speech (echolalia), inflexible routine, and atypical sensitivity to sensory input (Parritz & Troy, 2014, p. 123).

Previously, children were diagnosed with several different disorders under the category of autism. Children with more symptoms were diagnosed as autistic, while children who had more social and language skills were diagnosed as high-functioning autistic or Aspergers (Parritz & Troy, 2014, p. 120). Under the current DSM, all of these conditions are now considered autism spectrum disorder, with varying levels of support required (Parritz & Troy, 2014, p. 123).

Autism is frequently associated with comorbid disorders such as intellectual developmental disorder (IDD), attention-deficit hyperactivity disorder, and anxiety disorder (Parritz & Troy, 2014, p. 123). Although boys are more frequently diagnosed with autism than girls, girls with autism are more likely to have a comorbid diagnosis of IDD. The ADDM found that as many as 50% of children diagnosed with autism have an IDD (Christensen et al., 2016, p. 9). Half of children diagnosed with both ASD and IDD are nonverbal (Parritz & Troy, 2014, p. 129). A comorbid diagnosis of IDD can make interventions difficult even for children with speech and may impede their development (Matson & Horovitz, 2010, p. 1).


Current studies evaluated by the CDC estimate that 1 in 68 children have autism spectrum disorder (Data & Statistics, 2016). This is consistent with findings from international studies identifying children with autism at a rate between 1% and 2% (Data & Statistics, 2016). ASD is 4.5 times more likely to appear in boys than in girls (Data & Statistics, 2016). It is less likely to be diagnosed in black and Hispanic Americans, but it is unclear whether this is due to lower rate diagnosis of children with ASD or a lower level of susceptibility (New Data on Autism, 2016).

The estimated prevalence of children with autism has more than doubled since the Autism and Developmental Disabilities Monitoring Network(ADDM) began monitoring children in 2000 (Data and Statistics, 2016). Researchers are not convinced that the numbers show a true increase in autism but may be better explained as a reflection of diagnostic practices. According to Matson & Kozlowski (2011), “The relatively frequent change in diagnostic criteria appears to be at the core of the increasing prevalence of ASD” (p. 5). The public has also gained a greater awareness of autism since 2000 and may be more attentive to early warning signs. “More and more parents are having their children assessed who may not have previously done so” (Matson & Kozlowski, 2011, p. 6).


            Symptoms of autism persist throughout an individual’s lifetime. The severity of these symptoms depends on several factors. Comorbidity of autism with IDD is an indication of more severe symptoms throughout the life span (Matson & Horovitz, 2010, p. 8). Studies have shown that without quality intervention, symptoms of autism will remain stable and persistent over the course of an individual’s life (Matson & Horovitz, 2010, p. 7). Recent emphasis on early intervention hopes to change this, but at this time we do not have data which observes children over the course of their childhood and maturation into adults (Matson & Horovitz, 2010, p. 6). Time will tell how much interventions are able to improve adult symptoms of ASD. At this point, we know that early intervention can bring about great improvement in young children (Zachor et al., 2007, p. 12).

Individuals who have been diagnosed with autism rarely go into remission to the point of no longer receiving a diagnosis of ASD (Matson & Horovitz, 2010, p. 8). However, depending on the treatment they receive, they may receive a diagnosis of requiring less support than originally diagnosed (Zachor et al., 2007, p. 1). Those that do the best in response to interventions and adulthood are generally those that exhibited less severe symptoms initially and displayed a normal IQ (Matson & Horovitz, 2010, p. 8). Some adults with less severe symptoms of autism go on to have careers and even marriages, but many continue to struggle with relational challenges (Parritz & Troy, 2014, p. 132).


Christensen, D. L., Baio, J., Braun, K. V., Bilder, D., Charles, J., Constantino, J. N., . . . Yeargin-Allsopp, M. (2016). Prevalence and Characteristics of Autism Spectrum Disorder Among Children Aged 8 Years — Autism and Developmental Disabilities Monitoring Network, 11 Sites, United States, 2012. MMWR. Surveillance Summaries, 65(3), 1-23. doi:10.15585/mmwr.ss6503a1

Data & Statistics. (2016). Center for Disease Control and Prevention. Retrieved from http://www.cdc.gov/ncbddd/autism/data.html

Matson, J. L., & Horovitz, M. (2010). Stability of Autism Spectrum Disorders Symptoms over Time. Journal of Developmental and Physical Disabilities, 22(4), 331-342. doi:10.1007/s10882-010-9188-y

Matson, J. L., & Kozlowski, A. M. (2011). The increasing prevalence of autism spectrum disorders. Research in Autism Spectrum Disorders, 5(1), 418-425. doi:10.1016/j.rasd.2010.06.004

New Data on Autism: Five Important Facts to Know. (2016). Center for Disease Control and Prevention. Retrieved from http://www.cdc.gov/features/new-autism-data/index.html

Parritz, R. H., & Troy, M. F. (2014). Disorders of childhood: Development and psychopathology. Belmont, CA: Wadsworth Cengage Learning.

Zachor, D. A., Ben-Itzchak, E., Rabinovich, A., & Lahat, E. (2007). Change in autism core symptoms with intervention. Research in Autism Spectrum Disorders, 1(4), 304-317. doi:10.1016/j.rasd.2006.12.001





  1. I stumbled on your site (shockingly you are married to my cousin) and enjoyed reading your past posts on autism. We signed up for foster care a couple years ago. Because of the very backward county we live in with virtually no therapy options we told the workers “no special needs”. Long story but the last “normal child” they placed with us is very very autistic – 4 yrs old and not talking at all. It’s been a long hard surprise but we have learned to love him. The lack of good therapy continues to be my greatest struggle. The first year we had him I told the workers numerous times that I thought they needed to move him to a home in an area with better options. They said they were content with the little bit we are doing… I’m anxious to read your next posts on this subject!


    1. Sherilyn, I’m so glad you commented. I understand the frustration of the lack of therapy in rural communities; my family ran into the same thing with my sister. I’d love to dialogue more about possible resources and tools you could use; feel free to shoot me an email! Hopefully, the next post on resources and tools will also be helpful to you! Later on, I’ll also talk about IEPs, which work for things like communication and behavior, not just educational goals, so that may be beneficial for you as well.


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