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 PDD is.....

The term Pervasive Developmental Disorder (PDD) was coined by the American Psychiatric Association. It covers autism and related conditions such as Retts Syndrome or Fragile X Syndrome. It can broadly be seen as the umbrella term for all autistic spectrum and related disorders. In Europe the term Autistic Spectrum Disorder (ASD) is more commonly used to describe conditions which clearly fall on the autistic spectrum such as Asperger syndrome. Retts Syndrome et al are perceived as separate conditions with some related symptoms.

There is some debate as to which definition is superior. In the US they argue that the term PDD does not have the negative associations of the word autism. In Europe it is felt that the term is misleading as it implies that the condition is pervasive of all aspects of development. While children with autism may have profound/pervasive problems with the development of social and communication skills often their intellectual development is unimpaired.

However, the two terms are not going to go away. It is unlikely that the term PDD will supersede ASD in Europe in the near future, and the term PDD is now so widely used in the US that it would be hard to replace it. The impact this will have on the quality of diagnosis received by children with PDD/ASD is hard to assess.

One further problem with the widespread use of the term PDD is that it is increasingly used as an abbreviated way of referring to PDD-NOS (Pervasive Developmental Disorder Not Otherwise Specified). This condition was included only in the most recent edition of the 'Diagnostic and Statistic Manual of Mental Disorders (DSM-IV)'. The term refers to those people who have difficulties in more than one area but do not fulfil the diagnostic criteria for autism or Asperger Syndrome. As the name suggests this term should only be used when all other possible diagnoses have been eliminated and there is some concern that it is instead being offered as a positive diagnosis to parents whose children may have atypical autism or Asperger syndrome. In response to this, some more recent research has looked into the possibility of positive criteria for PDD-NOS being developed.

To summarise:

  • Pervasive developmental disorder is the umbrella term for all autistic and autistic like conditions. Someone with autism will have PDD but someone with PDD will not necessarily have autism.
  • There is some confusion over the use of the diagnostic term PDD-NOS. This should only ever be applied where all other diagnostic terms have been discarded already.
  • Debates as to what is the best diagnostic term to use are likely to continue.

© The National Autistic Society 2003