Between 1994 and 2013, autism was described in the Diagnostic and Statistical Manuals of the American Psychiatric Association, DSM IV and IVTR (Text Revision) as a psychological disorder distinguished by
  • poor sociability
  • poor communication
  • restricted and often repetitive behavioural repertoires, interests and activities
Such characteristics were applicable to children less than three years old. These behavioural descriptions (with some modifications along the way) have been in place since Leo Kanner and Hans Asperger first recognised them in them in the 1940s. ie some 70 years ago.
In DSM IV, there were five sub-categories of autism listed ie 
  • 299.00 Autistic Disorder
  • 299.10 Childhood Disintegrative Disorder
  • 299.80 Asperger’s Disorder
  • 299.80 Pervasive Development Disorder Not Otherwise Specified (PDDNOS)
  • 299.80 Rett’s Disorder
DSM-5 was issued on 18 May 2013 and now there are only two main diagnostic criteria for autism (Item 299), without age restriction ie
  • Persistent deficits in social communication and interaction
  • Restricted repetitive patterns of behaviour, interest or activities
However, there is now a requirement to indicate the severity of the symptoms in order to help identify the level of support they are likely to need. There are three levels as follows:
  • Requires support
  • Requires substantial support
  • Requires very substantial support
Rett’s and Asperger’s Disorders are no longer specifically included, though “Individuals with a well-established DSM-IV diagnosis of autistic disorder, Asperger’s disorder, or pervasive developmental disorder not otherwise specified should be given the diagnosis of autism spectrum disorder. Individuals who have marked deficits in social communication, but whose symptoms do not otherwise meet criteria for autism spectrum disorder, should be evaluated for social (pragmatic) communication disorder. []
Social (Pragmatic) Communication Disorder (Item 315.39) is a new category which covers deficits in using communication for social purposes.
As Rett’s Disorder has been attributed primarily, but not exclusively, to a genetic disorder (MECP2) since 1999, it has been withdrawn from within the autism spectrum.