There are five different types of Pervasive Developmental Disorders (PDDs) that are often considered to be types of Autism, but are actually different neurodevelopmental disorders. These are Autism or Autistic Disorder, Asperger’s Syndrome, Rett’s Disorder, Childhood Disintegrative Disorder, and Pervasive Developmental Disorder Not Otherwise Specified (PDD NOS). These five disorders are called “pervasive” instead of “specific developmental disorders”. They are different because they affect the development of many basic human functions, like communication and socialisation.

 

There follows a short introduction to the five main types of Disorders:

 

Autism, known as Classic Autism, Autistic Disorder, or Kanner’s Syndrome, was originally named and described by the Psychiatrist Leo Kanner from the John Hopkins University. His studies were based upon eleven of his child patients, during a period from 1932 to 1943, who had the common features of: lack of emotional contact with others, need for repetitive routines, speech abnormalities, a high level of visuospatial skills, the appearance of intelligence and alertness, and a desire to control things. These studies became the basis of all future understanding of this disorder.

 

Asperger’s Syndrome, or Disorder, is named after the studies of Hans Asperger in Vienna, in 1944. While there are similarities with Autism in that sufferers have impaired socialisation skills and desire repetitive patterns in their life; they don’t share the other learning disabilities in language and cognition. Often, those with Aspergerís will have an exceptional skill or talent which occupies them and many remarkable people, such as Einstein, have later been diagnosed with this disorder.

 

Rett’s Syndrome, or Disorder, was identified by Dr Andreas Rett in Australia in 1965. It is a neurodevelopmental degenerative disorder which only affects girls. It is similar to Autism, but with growth deformities such as muscle loss, and small hands and feet. It causes girls to become disabled and dependent upon others.

 

The disorder called Childhood Disintegrative Disorder (CDD), or Heller’s Syndrome named after the Austrian teacher Theodore Heller who first described it in 1908, is characterised by a seeming regression of skills by children after the age of two or three. It is similar to Autism but, instead, follows a normal development and is characterised by loss of skills.

 

The term Pervasive Developmental Disorder Not Otherwise Specified, or PDD NOS, is a catchall term used to refer to those who suffer disorders which aren’t specifically one or other of the four outlined above. Often this is a class of far milder symptoms, and types of autism, which tends to be emphasised by difficulties with socialisation.