was first described in the 1980s
in the UK,
by Elizabeth Newson, and is an Autistic Spectrum
Disorder related to, but significantly different from,
'standard' autism and Asperger's syndrome, and
is increasingly becoming recognised as part of
the autism spectrum.
Recently (February 2017) there has been
the change of language to PDA being a "profile
within the autism spectrum" and that is now
reflected on the NAS website and in some supporting
http://www.autism.org.uk/about/what-is/pda.aspx and http://www.pdasociety.org.uk/blog/2017/02/pda-profiles-nas-changes-and-new-article for more info.
Specifically, people with PDA will avoid demands made by others, due to their very sudden, and usually high, anxiety levels when they feel that they are not in control.
This PDA Resource website links to various recommended websites, Facebook pages, blogs, documents, graphics, & videos etc. and gathers together the best available information surrounding PDA, from sources around the world, to help parents, carers, professionals and others have a better understanding of PDA, and to provide help and support for people dealing with the condition.