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a doctor explains PDD


Definition of the PDD Category and Its Five Specific Disorders

The Cause of PDDNOS
The Symptoms and Signs of PDDNOS
Diagnosing PDDNOS
Special Education and PDDNOS
Treatment of PDDNOS
Finding a Parent Support Group
References, Resources and Organizations


Every year the National Information Center for Children and Youth with Disabilities (NICHCY) receives thousands of requests for information about the diagnosis, educational programming, and special needs of children and youth with Pervasive Developmental Disorders (PDD). Over the past few years, PDD has become a subject of increased attention among parents, professionals, and policymakers across the country.

NICHCY developed this Briefing Paper in response to the growing concern about, and interest in, this disability. This publication is designed to answer some of the most commonly asked questions regarding PDD and to provide concerned individuals with other resources for information and support.

The term Pervasive Developmental Disorders was first used in the 1980s to describe a class of disorders. This class of disorders has in common the following characteristics: impairments in social interaction, imaginative activity, verbal and nonverbal communication skills, and a limited number of interests and activities that tend to be repetitive.

The manual used by physicians and mental health professionals as a guide to diagnosing disorders is the Diagnostic and Statistical Manual of Mental Disorders (DSM). The DSM was last revised in 1994. In this latest revision, known as the DSM-IV, five disorders are identified under the category of Pervasive Developmental Disorders: (1) Autistic Disorder, (2) Rett's Disorder, (3) Childhood Disintegrative Disorder, (4) Asperger's Disorder, and (5) Pervasive Developmental Disorder Not Otherwise Specified, or PDDNOS.

Many of the questions parents and education professionals ask NICHCY have to do with children who have been diagnosed with "PDD." Doctors are divided on the use of the term PDD. Many professionals use the term PDD as a short way of saying PDDNOS. Some doctors, however, are hesitant to diagnose very young children with a specific type of PDD, such as Autistic Disorder, and therefore only use the general category label of PDD. This approach contributes to the confusion about the term, because the term PDD actually refers to a category of disorders and is not a diagnostic label. The appropriate diagnostic label to be used is PDDNOS--Pervasive Developmental Disorder Not Otherwise Specified--not PDD (the umbrella category under which PDDNOS is found).

Accordingly, this Briefing Paper will use the term PDD to refer to the overall category of Pervasive Developmental Disorders and the term PDDNOS to refer to the specific disorder, Pervasive Developmental Disorder Not Otherwise Specified. The majority of this Briefing Paper will focus on PDDNOS.

All of the disorders that fall under the category of PDD share, to some extent, similar characteristics. To understand how the disorders differ and how they are alike, it's useful to look at the definition of each disorder. Therefore, before we begin our discussion of PDDNOS, let us look first at the definition of the general category PDD and its specific disorders.

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This article is a publication of NICHCY and was reproduced with their permission. It is important to remember that this article was published in January 1998, and that therapies that may have appeared 'promising' then may have been totally discounted by now. -- L.P.








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