What is Pervasive Developmental Disorder?

The diagnostic category Pervasive Developmental Disorders (PDD) is an umbrella term for a group of disorders characterised by delays in the development of multiple basic functions including social understanding, behaviour and communication. The five disorders in this group are:

  • Autism
  • Rett Syndrome
  • Childhood Disintegrative Disorder
  • Asperger Syndrome
  • Pervasive Developmental Disorder Not Otherwise Specified, or PDD-NOS

The most commonly known PDD is Autism.

Parents may notice symptoms of PDD as early as infancy and typically onset is prior to 3 years of age. PDD itself generally does not affect life expectancy.

There is a division among doctors on the use of the term PDD. Many use the term PDD as a short way of saying PDD-NOS. Others use the general category label of PDD because they are careful to diagnose very young children with a specific type of PDD, such as autism. Both approaches cause confusion about the term, because the term PDD actually refers to a category of disorders and is not a diagnosis on its own.