PDD and ASD are the same thing. ASD is the much newer used term and I find a much clearer one.
Source: http://access.autistics.org/resources/g ... /main.html
Quote:
Pervasive Developmental Disorders (PDD) - Although sometimes incorrectly used to mean PDD-NOS or to avoid telling a parent their child has autism, PDD is not an actual diagnosis but a diagnostic category in the DSM-IV refering to a group of disorders characterized by delays in the development of multiple basic functions including socialization and communication. Symptoms may include communication problems such as using and understanding language; difficulty relating to people, objects, and events; unusual play with toys and other objects; difficulty with changes in routine or familiar surroundings, and repetitive body movements or behavior patterns. Pervasive developmental disorders, sometimes referred to as autistic spectrum disorders (ASD), include: Autistic Disorder, Asperger Syndrome (AS), Rett Syndrome (RS), Childhood Disintegrative Disorder (CDD), and Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS).
Both are terms that categorize the disorders on the autism spectrum. There is a higher incidence it seems in families that also have members on the autism spectrum than normal population, same with OCD.
There is a book out called "THE ADHD-AUTISM CONNECTION" by Diane M. Kennedy With Rebecca S. Banks, Paul T. Elliott M.D., & Carl Daisy, Contributors
The website is at:
http://www.adhdautismconnection.com/
She made a comment on one forum that it seems there seems to an increased misdiagnosis rate of ADHD before an AS diagnosis is made. Maybe ADHD is more similiar with traits to the autism spectrum disorders than one realizes, just like Hyperlexia and Sensory Processing Disorder or Apraxia.