What is PDD?

What is PDD?
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What is PDD? Introduction

Pervasive Developmental Disorders (PDD) are invasive and persistent disorders that affect and delay a child’s development in the key areas of communication and social skills. Typically, before the age of three, children with a disorder under the umbrella term of PDD exhibit delayed acquisition of speech and language, lack of interest in activities or interaction with other people, and often engage in repetitive awkward bodily movements and behaviors.

The four main types of pervasive developmental disorders are autism, Asperger’s syndrome, Childhood Disintegrative Disorder, and Rett’s syndrome. A fifth category covers general PDD-NOS (not otherwise specified) - variations of the initial four categories of disorders.

PDD-NOS may not strictly fit the characteristics of a specific disorder, but display components of two or more.[1][2]

What is PDD? Definition and Characteristics

Mental health providers use the Diagnostic and Statistical Manual as the standard for identifying and classifying mental and developmental disorders, as well as “for collecting and communicating accurate public health statistics.”[3] The following list is a summary of what is PDD, including five types of PDD, based on DSM criteria [4]:

1. Autism: typically presents between 18 to 36 months of age as delay or regression in speech development and social interaction. DSM criteria include the following primary characteristics: poor eye contact, pervasive ignoring, and language delay. Many autistic children are non-verbal and remain isolated from their peers.

2. Asperger’s syndrome: presents as a high-functioning form of autism, although not as a delay in speech development, but rather as difficulty with appropriate speech and social communication. These children typically exhibit compulsive, repetitive behavior, and lack self-care skills. They also lack the ability to distinguish non-verbal cues, such as facial expressions, body language, tone of voice, or emotional reactions.

3. Childhood Disintegrative Disorder: presents after normal development for the first three years of life, resulting in regression of acquired skills and increased functional impairment accompanied by autistic features. These children often develop seizures that affect the speech areas of the brain. The outlook for children with CDD is dismal, as the loss of skills often results in the need for constant care and potential institutionalization.

4. Rett’s syndrome: presents as a condition that primarily affects girls who develop normally up until six months of age, but this is followed by slowed head and brain growth. Other symptoms include seizures, sensory problems and loss of speech.

5. PDD-NOS: presents similar to symptoms of autism and Asperger’s syndrome, although with less severe impairment. These children typically have some degree of verbal capacity, but still exhibit difficulties with communication and social interaction, as well as displaying compulsive behavior. This diagnosis usually applies to children who do not fit under another specific PDD category.


Pervasive Developmental Disorders (PDD) are those persistent and invasive disorders that delay children’s development primarily in the areas of communication and social skills. The symptoms typically manifest prior to the age of three, and children with one of the disorders classified under PDD often experience delayed acquisition of language skills, seem disinterested in interacting with other people, and engage in compulsive, repetitive bodily movements and behaviors.


[1] National Institutes of Health - National Institute of Neurological Disorders. Pervasive Developmental Disorders. Retrieved from https://www.ninds.nih.gov/disorders/pdd/pdd.htm

[2]All Psych Online. Diagnostic and Statistical Manual of Mental Disorders. Retrieved from https://allpsych.com/disorders/dsm.html

[3]American Psychiatric Association. Diagnostic and Statistical Manual. Retrieved from https://www.psych.org/mainmenu/research/dsmiv.aspx

[4]Childbrain.com. PDD. Retrieved from https://www.childbrain.com/pddq4.shtml


Autism-Help.org. Autism, Asperger’s syndrome, PDD-NOS, and related disorders. Retrieved from https://www.autism-help.org/index.htm

*Childbrain.com. The DSM IV criteria for the autistic disorders. Retrieved from https://www.childbrain.com/pddq3.shtml

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