Clarification of the definition of Pervasive Developmental Disorder Not Otherwise Specified
Autism was first included in Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM-III) in 1980 in a new class of conditions--the Pervasive Developmental Disorders (PDD). A residual category, Atypical PDD, was also included and encompassed difficulties characterized by problems in social interaction and problems in communication or restricted/unusual interests similar to those observed in autism but which did not meet full criteria for either infantile autism or childhood onset pervasive developmental disorder. By implication, individuals with Atypical PDD had to exhibit some problem in the social area and either in communication or unusual interests. In Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised (DSM-III-R) the name for the subthreshold class was changed to Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS) but otherwise the approach to diagnosis was the same.
Major changes were made the PDD category in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) based, in part, on a large, multi-site, international field trial. However, an editorial change was made in the description of PDDNOS during the final phase of production that had an unintended effect on the definition of PDDNOS. Instead of requiring “impairment in social interaction and in verbal or nonverbal communication skills” (DSM-III-R, p. 39), DSM-IV states that the “category should be used where there is a severe and pervasive impairment of reciprocal social interaction or verbal and nonverbal communication skills, or when stereotyped behavior, interests, and activities are present” (DSM-IV, pp. 77-78). Thus, a child with an impairment in only one area (e.g., a child with stereotyped behavior, interests and activities but without evidence of disturbed social interactions could theoretically qualify for a diagnosis of PDDNOS.
To assess the impact of the DSM-IV wording, Volkmar and colleagues performed a series of reanalyses of the DSM-IV autism/PDD field trial data (Volkmar FR, Shaffer D, First M. PDD-NOS in DSM-IV. J Autism Dev Disord 2000 Feb;30(1):74-75). A series of comparisons were conducted to evaluate sensitivity/specificity. Using clinicians' judgment of the presence or absence of PDDNOS as the standard, the DSM-IV wording had an excellent sensitivity of .98. However, the specificity was only .26, i.e., about 75% of cases identified by the clinician as not having PDDNOS (true negatives), were incorrectly identified as having PDDNOS according to the DSM-IV. These results lend support to the concern that the DSM-IV wording inappropriately broadened the PDDNOS construct. If problems are required in the social area and either communication or restricted interest (i.e., at least 2 criteria present one of which must be from the social area) the sensitivity was .89 and specificity .56.
These results supported a change in the wording of PDDNOS to revert to the original construct. The new wording in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) is as follows:
“This category should be used when there is a severe and pervasive impairment in the development of reciprocal social interaction associated with impairment in either verbal and nonverbal communication skills, or with the presence of stereotyped behavior, interests, and activities, but the criteria are not met for a specific Pervasive Developmental Disorder, Schizophrenia, Schizotypal Personality Disorder, or Avoidant Personality Disorder.”