According to the earlier DSM-IV, PDD-NOS referred to "mild or severe pervasive deficits in the development of reciprocal social interaction and/or verbal and nonverbal communication skills, or when stereotyped behavior, interests, and/or activities are present, but the criteria are not met for a specific PDD" or for several other disorders.
[8] The diagnosis of a pervasive developmental disorder not otherwise specified was given to individuals with difficulties in the areas of social interaction, communication, and/or stereotypic behavior patterns or interests, but who did not meet the full DSM-IV criteria for autism or another PDD.
[4] As for the other pervasive developmental disorders, the diagnosis of PDD-NOS required 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.
[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.