PDD-Not Otherwise Specified [PDD-NOS]

What is PDD-NOS?

Pervasive Developmental Disorder, Not Otherwise Specified (PDD-NOS) is a 'subthreshold' condition in which some - but not all - features of autism or another explicitly identified Pervasive Developmental Disorder are identified. PDD-NOS is often incorrectly referred to as simply "PDD." The term PDD refers to the class of conditions to which autism belongs. PDD is NOT itself a diagnosis, while PDD-NOS IS a diagnosis. The term Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS; also referred to as "atypical personality development," "atypical PDD," or "atypical autism") is included in DSM-IV to encompass cases where there is marked impairment of social interaction, communication, and/or stereotyped behavior patterns or interest, but when full features for autism or another explicitly defined PDD are not met.

It should be emphasized that this ''subthreshold'' category is thus defined implicitly, that is, no specific guidelines for diagnosis are provided. While deficits in peer relations and unusual sensitivities are typically noted, social skills are less impaired than in classical autism. The lack of definition(s) for this relatively heterogeneous group of children presents problems for research on this condition. The limited available evidence suggest that children with PDD-NOS probably come to professional attention rather later than is the case with autistic children, and that intellectual deficits are less common. [More Information]

Common Characteristics of PDD-NOS

There are several specific 'symptoms' from a list in the DSM-IV-TR related to these difficulties, that children must show in order to meet the criteria for Autistic disorder, some of which include:

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Causes of PDD-NOS

There is no known single cause for autism, but it is generally accepted that it is caused by abnormalities in brain structure or function. Brain scans show differences in the shape and structure of the brain in autistic versus non-autistic children. Researchers are investigating a number of theories, including the link between heredity, genetics and medical problems. In many families, there appears to be a pattern of autism or related disabilities, further supporting a genetic basis to the disorder. While no one gene has been identified as causing autism, researchers are searching for irregular segments of genetic code that autistic children may have inherited. It also appears that some children are born with a susceptibility to autism, but researchers have not yet identified a single "trigger" that causes autism to develop. [More Information]

Diagnosis of PDD-NOS

Doctors should do a “developmental screening” at every well-baby and well-child visit, through the preschool years. In this screening, the doctor asks questions related to normal development that allow him or her to measure a specific child’s development. These questions are often more specific versions of the “red flags” listed above, such as Does the child cuddle like other children? Or, Does the child direct your attention by holding up objects for you to see? A doctor should definitely and immediately evaluate a child for autism if he or she:

Does not babble or coo by 12 months of age
Does not gesture (point, wave, grasp, etc.) by 12 months of age
Does not say single words by 16 months of age
Does not say two-word phrases on his or her own (rather than just repeating what someone says to him or her) by 24 months of age
Has any loss of any language or social skill at any age

If the doctor finds that a child either has definite signs of autism, or has a high number of red flags, he or she will send the child to a specialist in child development or another type of health care professional, so the child can be tested for autism. The specialist will rule out other disorders and use tests specific to autism. Then he or she will decide whether a formal diagnosis of autism, ASD, or another disorder is appropriate. [More Information]

Support Groups

The stress of illness can often be helped by joining a support group where members share common experiences and problems. [Find Local Chapters]