How Does Pervasive Developmental Disorder Differ from Asperger’s Syndrome?

How Does Pervasive Developmental Disorder Differ from Asperger's Syndrome?

If you are familiar with autism spectrum disorder or developmental disabilities, you have probably heard the terms Pervasive Developmental Disorder and Asperger’s Syndrome.  Before 2013, when the American Psychiatric Association Diagnostic and Statistical Manual of Mental Disorders (DSM) made significant updates to the diagnosis of autism, there were five separate categories of pervasive developmental disorders.  They included:

  • Autistic Disorder
  • Asperger’s Disorder
  • Childhood Disintegrative Disorder
  • Rett Syndrome
  • Pervasive Developmental Disorder

The latest edition of the DSM (DSM-5) removed the category of “pervasive developmental disorders”, placing these conditions under the autism spectrum disorder diagnosis under the category of “neurodevelopmental disorders.”   While these individual terms are no longer used, it is important to understand PDD-NOS and Asperger’s Syndrome and how the current DSM-5 diagnoses these conditions.

What is Asperger’s Syndrome?

What is Asperger's Syndrome?

Although Asperger’s syndrome is not technically a diagnosis any longer, many people still use the term.  This subtype of autism was considered “high-functioning” autism.  Children and adults with this form of autism typically have difficulties with social interactions and understanding social norms. Their range of interests is usually restricted.  They may also exhibit repetitive behaviors. According to Autism Speaks, people with Asperger’s may also have:

  • developmental delays
  • uncoordinated motor movements
  • general clumsiness

Compared to more severe forms of autism, individuals with Asperger’s Syndrome don’t usually have significant delays in language or cognitive development. Even though they may have restricted interests, those with this type of autism tend to be very intelligent and specialized within those fields of interest.

The most common behaviors and/or symptoms of Asperger’s Syndrome are as follows:

  • Repetitive speech
  • Inappropriate or limited social interactions
  • Nonverbal communication challenges (facial expressions, lack of eye contact, etc.)
  • Overall inability to understand social or emotional issues
  • Obsession with very specific topics
  • Tendency to hold one-sided conversations
  • Awkward mannerisms
  • Possible developmental delays, although not significant

Asperger’s can look similar to attention deficit hyperactivity disorder.  In fact, the DSM-5 recognizes that these two disorders do co-occur.  In fact, Children and Adults with Attention-Deficit/Hyperactivity Disorder (CHADD) reports that over half of individuals with an autism diagnosis have signs or symptoms of ADHD.

What is Pervasive Developmental Disorder (PDD-NOS)?

What is Pervasive Developmental Disorder (PDD-NOS)?

In the DSM-IV, this subtype of autism was considered the mildest form on the spectrum. Also known as Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS), this diagnosis became the go-to answer for children and adults who can be classified on the autism spectrum, but do not completely meet the criteria for the other subtypes. According to Autism Speaks, the diagnostic criteria for pervasive developmental disorder included, “someone who has some but not all characteristics of autism or who has relatively mild symptoms.”

PDD-NOS could be used in the absence of these diagnoses:

  • specific pervasive developmental disorder
  • schizophrenia
  • schizotypal personality disorder
  • avoidant personality disorder

PDD-NOS was considered “atypical autism” in that individuals had symptoms but didn’t meet the level of support needed for an autistic disorder diagnosis.

While PDD is no longer considered a diagnosis by the DSM-5, learning about this disorder can help better understand ASD.

What Does PDD NOS in Adults Look Like?

It is widely believed PDD (and autism in general) in adults often goes undiagnosed.  Since most autism diagnoses are given to children, adults are largely unrepresented.   Many pervasive developmental disorder adult diagnoses are made because a friend or family member referred an individual for testing.  Pervasive developmentally delayed adults might seek testing if they believe some of the symptoms they’ve experienced throughout their life could be related to autism.  Some of these symptoms might include:

  • Having trouble interpreting body language
  • Finding it difficult to make small talk or deficits in communication skills
  • Uncertainty about when to ask questions or speak up
  • Difficulty coping with change
  • Using the wrong voice tone or volume for a situation

PDD NOS vs Asperger’s Syndrome

Today, both PDD NOS and Asperger Syndrome are absorbed under the umbrella of autism spectrum disorders.  Historically, they were unique diagnoses.  Like Asperger’s, those with PDD tend to have significant challenges when it comes to social and language development. This diagnosis is typically used for people who meet the basic requirements for autism, but do not exhibit the more severe characteristics, like:

  • extreme repetitive behaviors
  • intellectual limitations
  • inappropriate mannerisms

A person may be diagnosed with PDD if they exhibit social and communication challenges, but simply do not exhibit other symptoms of Asperger’s, like:

  • obsessions over certain topics
  • developmental delays
  • awkward mannerisms

People with pervasive developmental disorder not otherwise specified typically live mostly ordinary lives.  PDD is considered the highest functioning of all autism subtypes, but individuals can have:

  • issues relating to people
  • understanding language
  • accepting change in surroundings or routines
  • dealing with their own emotions

ASD and the DSM-5 – A New Approach to Diagnosing ASD

The DSM-5 provides standardized criteria to help providers properly diagnose autism spectrum disorders.  In order to receive a diagnosis, an individual must have deficits in each of the three areas of social communication and interaction.  These areas include:

  • social-emotional reciprocity
  • nonverbal communicative behaviors used for social interaction
  • developing, maintaining, and understanding relationships

In addition to deficits in all three of these areas, an individual must have deficits in at least two of the following types of restricted, repetitive behaviors including:

  • stereotyped or repetitive motor movements, use of objects, or speech
  • insistence on things staying the same, difficulty adapting to changes in routine, ritualized patterns of behavior
  • very restricted interest or fixations that are not normal in their intensity
  • hyper or hyporeactivity to sensory input

These symptoms must meet the following criteria:

  • be present in the early developmental period
  • cause significant impairment
  • not better explained by another intellectual disability or global developmental delay

Since autism is a spectrum disorder, individuals on the spectrum can vary widely in their abilities and intelligence.  Some individuals will have relatively normal language development while other individuals do not speak at all.  Other individuals are hypersensitive to noises or lights while others don’t seem as bothered.  Each person is unique and the autism spectrum disorder diagnosis acknowledges that the disorder is a continuum.

Of course, early diagnosis and intervention are critical.  Children with an appropriate diagnosis can get the services and treatment they need to be successful in mainstream classrooms.  It is never too late to start behavioral therapy though.  Behavioral therapy can help individuals deal with symptoms they are experiencing and overcome challenges.

Related Resource

Autism spectrum disorders can be a difficult topic to understand.  This is especially true for those trying to figure out if they or someone they know fit into one of the many categories. Affecting almost 1 in 68 children, it’s important to understand the symptoms and be as proactive as possible. The information here will help you better understand the slight differences between PDD NOS vs Asperger’s syndrome and the updated diagnostic criteria for autism spectrum disorders.