Types Of Autism & How To Identify Them

Today we’ll cover the types of autism spectrum disorder, as well as how to identify them.

Steven Zauderer

August 4, 2025

Types Of Autism: Myths Debunked

Before 2013, children were often diagnosed with one of four types of autism:

Autism Spectrum Disorder (ASD)
Asperger's Syndrome
Childhood Disintegrative Disorder (CDD)
Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS)

According to the American Psychiatric Association (APA), the four "types" of autism are best grouped as a single diagnosis because of their similarities, and because they are all categorized by severity, this was another reason the APA decided to group them.

Now, when a child is classified as autistic, the broad term that is used is Autism Spectrum Disorder or ASD.

However, the previous autism diagnosis still has a place in how a child with ASD is treated.

So, we will discuss the previous type of diagnosis to help you better understand the differences and how they might be treated.

Autism Spectrum Disorder (ASD)

Autism was not considered to be a diagnosis until 1980 when it appeared in the DSM-III, and three essential features needed to be present for the disorder to be diagnosed.

Plus, all of these features had to be present within the first 30 months of life. Here are the three essential features that were needed to be diagnosed with autistic disorder:

Having a bizarre response to the environment - This could be a resistance to change or a particular interest in objects.
Lack of interest in people or socialization - This could be with siblings, parents, or peers.
Severe impairments in language and communication areas - For instance, if a child had speech, but they used peculiar speech patterns, like echolalia.

Asperger's Syndrome

Asperger's Syndrome/Disorder was first recognized and diagnosed in 1994, and the stipulations for this diagnosis were revised later in 2000.

Unlike other autistic disorders, people who were diagnosed with Asperger's Disorder often had average or above-average intelligence.

However, despite their intelligence level, these children still had a lot of challenges, but their challenges dealt more with emotional regulation, repetitive interests, and socializing with others.

Asperger's Disorder is often not caught or diagnosed until a child is placed in a situation where their socializing reveals the disorder, like preschool or elementary school.

However, in some cases, Asperger's Disorder could be diagnosed earlier, but like most autism disorders, depending on the severity of the diagnosis, it could be noticed earlier in life.

Childhood Disintegrative Disorder (CDD)

Childhood Disintegrative Disorder wasn't included in the DSM until the DSM-IV was released in 1994. CDD was considered to be a late-onset form of ASD because it included severe regressive signs of the autism spectrum.

Unlike many autistic children who had issues in socializing, language skills, or other emotional issues, children who were diagnosed with CDD often didn't start with the same issues.

Many of these children seemed to be developing naturally like the average child, but at some point in their development, they would begin to regress, meaning the loss of skills they had already mastered, whether it be in language, emotional, or social skills.

Children who were diagnosed with CDD were considered to be severely more impaired than children who were diagnosed with ASD.

They typically suffered from lower IQs, and they were at a higher risk of being diagnosed with epilepsy. However, CDD is no longer considered a viable autism diagnosis.

Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS)

Pervasive Developmental Disorder - Not Otherwise Specified was added as an autism disorder in 1987 in the DSM-III, which featured several significant changes in how professionals diagnosed autism.

PDD-NOS was a diagnosis on the mild end of the autism spectrum, even though the word "spectrum" wasn't used at the time.

The addition of PDD-NOS was a turning point in professionals' understanding of autism, and it started the shift in that understanding for subsequent years.

Before the changes in 2013, PDD-NOS was the go-to diagnosis for individuals who appeared o the autism spectrum but didn't meet the individual criteria for the other diagnosis, like autistic disorder or Asperger's disorder.

For example, someone who was diagnosed with PDD-NOS, might not have issues with socializing with other individuals, but they didn't experience repetitive behaviors or other signs of ASD. Therefore, they were diagnosed with PDD-NOS.