What Is Atypical Autism?

atypical autism

While autism presents itself differently in every individual, some people display only some signs of this mysterious disorder. If you or your child have some of the symptoms of autism or experience difficulties in only two the three core areas, you may have atypical autism or, as it's officially called, Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS). People with atypical autism still require help in their areas of challenge, but they may also excel in areas that can be difficult for individuals with classic autism.

Diagnostic Criteria for Atypical Autism or PDD-NOS


Contrary to the name, atypical autism actually has a lot in common with classic autism. PDD-NOS is considered an autism spectrum disorder (ASD). Individuals with PDD-NOS may struggle with many of the same challenges as those with classic autism; however, they may be completely symptom-free in other areas. Additionally, atypical autism or PDD-NOS is often diagnosed at a later age than classic autism, partially because the individuals with atypical autism are less severely affected and may not draw as much attention. To be diagnosed with PDD-NOS, an individual must meet the criteria laid out in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV).

Two of the Three Core Diagnostic Criteria for Classic Autism

While classic autism is comprised of challenges in behavior, communication, and social skills, atypical autism does not necessarily involve all three of those core areas. According to the Autism Society, mental health professionals diagnose PDD-NOS when an individual struggles with stereotyped, repetitive behaviors and has trouble with at least one of the following:

  • Social skills, including reciprocal (back-and-forth) interaction
  • Communication skills, including verbal and non-verbal communication

Sub-Threshold or Atypical Symptoms

The DSM-IV states that those diagnosed with PDD-NOS or atypical autism will have sub-threshold or atypical symptoms. This means that they may experience some of the symptoms of autism to a lesser extent, and they often may not experience enough of the classic autism symptoms to warrant a full autism diagnosis. This can be frustrating for parents who are worried about their child's development or for individuals who need help with certain areas but don't quite fit the classic autism diagnosis.

If you or your child has atypical autism, you may struggle with some but not all of these symptoms:

  • Difficulty using and understanding non-verbal communication behaviors like gestures, nodding, eye contact, facial expressions, and posture
  • Lack of empathy or sharing emotion
  • Lack of age-appropriate peer friendships
  • Lack of pretend play or symbolic play
  • Repetition of speech or lack of meaningful language
  • Failure to "share attention," such as showing objects to someone, pointing at something of interest, and following another's pointed finger
  • Delayed speech
  • Strong interest in a narrow subject area, such as trains, machines, animals, etc.
  • Difficulty having a conversation
  • Driven to adhere to a routine
  • Strong interest in objects or parts of objects, often independent of their functional use
  • Repetitive movements, such as hand flapping, rocking, or tapping

PDD-NOS, or Atypical Autism, to Be Removed from DSM-V

It's important to note that PDD-NOS or atypical autism will likely be removed as a diagnosis when the next edition of the DSM is released in May of 2013. According to the American Psychiatric Association DSM-V Development site, individuals meeting the previous diagnostic criteria for PDD-NOS will receive the diagnosis of autism spectrum disorder. This is also the case for Asperger's Syndrome. According to Psychology Today, this change may mean that those who already carry a diagnosis of atypical autism may need to be re-evaluated and re-diagnosed.

Atypical Autism in Children and Adults

Since people with PDD-NOS can experience different levels of impairment involving a variety of symptoms, this disorder presents itself differently in everyone. In children, the often milder impairments that come with PDD-NOS may mean that the child doesn't receive therapy and educational help until they are older.

Many adults, who grew up in a time when autism spectrum disorders were often misunderstood, may have developed very effective coping mechanisms on their own. However, if adults were significantly impaired enough to receive a diagnosis during early childhood, they may still display many of the same symptoms as adults. One study published in the Journal of Child Psychology and Psychiatry found that individuals who were diagnosed with atypical autism before the age of five still displayed marked social impairments as adults. There was no mention of the type of therapy used to treat these individuals in childhood.

What to Do if You Suspect Atypical Autism

If you're worried that you or your child has some or many of the characteristics of PDD-NOS, talk to your doctor right away. Just like any autism spectrum disorder, getting help early can make a huge difference in an individual's life. Learning coping mechanisms, which are often similar to those used in classic autism treatment, can help you or your child overcome the challenges and go one to have a happy and fulfilling adult life.

Was this page useful?
What Is Atypical Autism?