Pervasive Developmental Disorder (Not Otherwise Specified) is a form of autism. It is also known as PDD(NOS) or atypical autism.
PDD(NOS) is used to describe people who don't fit neatly into one of the specific kinds of autism, such as autistic disorder, Asperger syndrome or childhood disintegrative disorder.
The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, published in 2013, eliminates PDD(NOS) as a formal diagnosis by dissolving it and other subtypes of autism into one diagnosis called autism spectrum disorder.
The 11th edition of the International Classification of Diseases and Related Health Problems, published in 2020, eliminated PDD(NOS) as a formal diagnosis by dissolving it and other subtypes of autism into one diagnosis called autism spectrum disorder.
The 10th edition of the International Classification of Diseases and Related Health Problems, published in 2010, states that 'atypical autism' is
'A type of pervasive developmental disorder that differs from childhood autism either in age of onset or in failing to fulfil all three sets of diagnostic criteria. This subcategory should be used when there is abnormal and impaired development that is present only after age three years, and a lack of sufficient demonstrable abnormalities in one or two of the three areas of psychopathology required for the diagnosis of autism (namely, reciprocal social interactions, communication, and restricted, stereotyped, repetitive behaviour) in spite of characteristic abnormalities in the other area(s). Atypical autism arises most often in profoundly retarded individuals and in individuals with a severe specific developmental disorder of receptive language.'
There are many possible causes of the different forms of autism including Pervasive Developmental Disorder - Not Otherwise Specified. For example, according to the Medical Research Council.
'Most researchers believe that ASDs have a variety of causes, perhaps all affecting the same brain systems, or impeding development through disruption of different abilities necessary for social and communicative development.Whether environmental factors interact with genetic susceptibility is as yet unclear.'
Recent studies state that the number of people with all forms of autism cannot be precisely fixed, but it appears to be around 1 in 100 people. We do not know how many of these have Pervasive Developmental Disorder - Not Otherwise Specified.
PDD - NOS is present from birth, although the symptoms may not be immediately obvious. It is four times more common in boys than in girls.
The 11th edition of the International Classification of Diseases and Related Health Problems, which is due for publication in 2019, is likely to eliminate pervasive developmental disorder (not otherwise specified) as a formal diagnosis by dissolving it and other subtypes of autism into one diagnosis called autism spectrum disorder.
According to the International Classification of Diseases and Related Health Problems - 10th Edition, 'atypical autism' is
'A type of pervasive developmental disorder that differs from childhood autism either in age of onset or in failing to fulfil all three sets of diagnostic criteria. This subcategory should be used when there is abnormal and impaired development that is present only after age three years, and a lack of sufficient demonstrable abnormalities in one or two of the three areas of psychopathology required for the diagnosis of autism (namely, reciprocal social interactions, communication, and restricted, stereotyped, repetitive behaviour) in spite of characteristic abnormalities in the other area(s). Atypical autism arises most often in profoundly retarded individuals and in individuals with a severe specific developmental disorder of receptive language.'
The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders published in 2013 eliminates pervasive developmental disorder (not otherwise specified) as a formal diagnosis by dissolving it and other subtypes of autism into one diagnosis called autism spectrum disorder . According to the American Psychiatric Association, this represents an effort to more accurately diagnose all individuals showing the signs of autism.
According to the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders people with pervasive developmental disorder (not otherwise specified) share most of the symptoms found in other people with autism.
However individuals with PDD - NOS.
Each individual will experience these symptoms to a different extent. For example, a child may have little trouble learning to read but exhibit extremely poor social interaction. Each child will display communication, social, and behavioral patterns that are individual but fit into the overall diagnosis of autism.
Individuals with pervasive developmental disorder - not otherwise specified, like other individuals on the autism spectrum, are more likely to have a range of related conditions (comorbidities).
For example, they are more likely to have genetic syndromes (such as Fragile X Syndrome), medical conditions (such as epilepsy) or other developmental disabilities (such as ADHD).
People with pervasive developmental disorder (not otherwise specified) face many issues, including some problems and some challenges, on a day to day basis.
For example, they may find it difficult to communicate with other people or to socialise with them. And they may have additional conditions, such as epilepsy or gastro-intestinal problems, which bring their own issues.
Please see Issues, Problems and Challenges
Individuals with Pervasive Developmental Disorder - Not Otherwise Specified (like other people with autism) vary enormously but most will find it hard to cope with other people, to work or to function independently.
Realistically, some can be expected to continue to need some degree of assistance as adults.
In severe form the condition may require intensive, specialised, life long care and support.
Without timely and informed help and support there can be potentially devastating consequences for people with PDD - NOS and those around them.
An intervention is any kind of activity (such as a treatment, a therapy or the provision of a service) that is designed to improve the quality of life for people on the autism spectrum
There are many different types of intervention and the names and numbers of interventions are increasing all the time.
Some interventions are designed to address the core features of PDD-NOS (persistent difficulties with social communication and social interaction, along with restricted, repetitive patterns of behaviour, interests, or activities).
Other interventions are designed to address other issues (such as anxiety, aggression or self injurious behaviour).
Some interventions can be quite simple and straightforward. For example, if someone finds a specific situation difficult (such as being in a noisy, crowded room) you can change the situation (by reducing the noise in the room or by not asking the person to be in that room).
Other interventions may be more complex, requiring a team of professional experts and/or expensive materials and implemented over the course of many years.
Unfortunately some interventions are scientifically unfeasible and potentially hazardous. And there is currently very little scientific research to support the use of some interventions despite sometimes extravagant and misleading claims about their effectiveness.
What the research does show is that, while there is no cure for PDD-NOS, some interventions do appear to help at least some individuals.
However there is no 'one-size fits all' solution. Each person with PDD-NOS is a unique individual, with unique needs and abilities. The most effective interventions follow some key principles, such as being tailored to meet the unique characteristics of each individual.
This page provides details of some of the most significant studies and reviews on pervasive developmental disorder (not otherwise specified).
You can find more studies and reviews on PDD (NOS) in our publications database.
If you know of any other publications we should list on this page please email info@informationautism.org
Please note that we are unable to supply publications unless we are listed as the publisher. However, if you are a UK resident you may be able to obtain them from your local public library, your college library or direct from the publisher.
This section provides details of other publications on pervasive developmental disorder (not otherwise specified) and related issues.
You can find more publications on PDD (NOS) in our publications database.
If you know of any other publications we should list on this page please email info@informationautism.org
Please note that we are unable to supply publications unless we are listed as the publisher. However, if you are a UK resident you may be able to obtain them from your local public library, your college library or direct from the publisher.