Pervasive developmental disorder not otherwise specified

It is common for individuals with PDD-NOS to have more intact social skills and a lower level of intellectual deficit than individuals with other PDDs.[3] Characteristics of many individuals with PDD-NOS are:

• Communication difficulties (e.g., using and understanding language)[7]
• Difficulty with social behavior
• Difficulty with changes in routines or environments
• Uneven skill development (strengths in some areas and delays in others)
• Unusual play with toys and other objects
• Repetitive body movements or behavior patterns
• Preoccupation with fantasy, such as imaginary friends in childhood

PDD-NOS is an old diagnostic category. It is not included as an option for an Autism Spectrum Disorder and is not part of the DSM-5, but is included in the ICD-10, as either "atypical autism" or "pervasive developmental disorder, unspecified".[8]

The diagnosis of a pervasive developmental disorder not otherwise specified is given to individuals with difficulties in the areas of social interaction, communication, and/or stereotypic behavior patterns or interests, but who do not meet the full DSM-4 criteria for autism or another PDD. This does not necessarily mean that PDD-NOS is a milder disability than the other PDDs. It only means that individuals who receive this diagnosis do not meet the diagnostic criteria of the other PDDs, but that there is still a pervasive developmental disorder that affects the individual in the areas of communication, socialization, and behavior.[3]

As for the other pervasive developmental disorders, the diagnosis of PDD-NOS requires the involvement of a team of specialists. The individual needs to undergo a full diagnostic evaluation, including a thorough medical, social, adaptive, motor skills and communication history.[3] Other parts of an assessment can be behavioral rating scales, direct behavioral observations, psychological assessment, educational assessment, communication assessment, and occupational assessment.[9]

Description of PDD-NOS merely as a "subthreshold" category without a more specific case definition poses methodological problems for research regarding the relatively heterogeneous group of people who receive this diagnosis. While it's true that children diagnosed with PDD-NOS, as a whole, show fewer intellectual deficits and are higher-functioning than autistic children, many others who fit the criteria for PDD-NOS have some autistic features but also have intellectual deficits that are so severe that it's difficult or impossible to tell whether some of the deficits come from the autism or from the severe to profound degree of intellectual disability itself. Furthermore, some others who fit the criteria for PDD-NOS come to professional attention at a later age, compared to those diagnosed with autism.[10] [11]

There is no known "cure" for PDD-NOS, but there are interventions that can have a positive influence. Early and intensive implementation of evidence-based practices and interventions are generally believed to improve outcomes. Most of these are individualised special education strategies rather than medical or pharmaceutical treatment; the best outcomes are achieved when a team approach among supporting individuals is used.

Some of the more common therapies and services include:[3]

• Visual and environmental supports, visual schedules
• Social stories and comic strip conversations
• Speech therapy
• Physical and occupational therapy[3]