DSM-5 and DSM-IV-TR Comparisons:
The following is a statement released from APA Intellectual and Developmental Disabilities (Division 33) regarding the recent changes to the previous PDD category:

Moving Forward: Understanding the DSM-5 Criteria for Autism Spectrum Disorder
James McPartland,
Child Study Center, Yale University School of Medicine

    The American Psychiatric Association published the Fifth Edition of the Diagnostic and Statistical Manual of Mental Disorders in May (2013). Among changes to numerous psychiatric and developmental disorders, this revision introduced a significant restructuring of the diagnostic criteria for autism. Most of these alterations were made public in January 2011, with the posting of the then draft criteria. This article will first review the changes presented in initial drafts and summarize research conducted to examine implications of these draft criteria. Next, the additional revisions revealed in May 2013 will be discussed, along with the questions they raise for clinicians and researchers in the coming months.

    Major changes to ASD were evident in the January 2011 draft criteria. The class of Pervasive Developmental Disorders (PDDs) was merged into a single class of Autism Spectrum Disorder (ASD). This umbrella category subsumed the previously distinct PDDs of Autistic Disorder, Asperger’s Disorder and Pervasive Developmental Disorder – Not Otherwise Specified (PDD‐NOS). The classic “triad” of impairments spanning social behavior, communication, and repetitive and restricted behaviors was collapsed into two categories, preserving restricted and repetitive behaviors and merging social and communicative difficulties into a single domain of difficulties in social communication and social interaction. This social‐communication category was made monothetic, requiring that a person demonstrate symptoms across all three clusters to meet criteria for ASD. The restricted and repetitive behaviors domain remained polythetic, requiring presence of symptoms in two of four clusters, and added a symptom cluster reflecting sensory difficulties. A universal onset criterion was implemented, specifying that symptoms must be present in early development. A new diagnostic category, Social Communication Disorder (SCD), defined by pragmatic difficulties and problems in the use of verbal and nonverbal communication in social contexts was introduced as a distinct disorder from ASD.

    Subsequent to the posting of these proposed criteria, extensive discussion has taken place in both academic contexts and the popular media. A particular focus has been on whether these revisions could affect the proportion of individuals meeting criteria for ASD  compared to DSM‐IV‐TR. For example, the inclusion of sensory symptoms could lead to additional individuals meeting criteria; conversely, the requirement of multiple symptoms in the domain of restricted and repetitive behaviors could lead to individuals currently meeting criteria failing to do so.  A re‐examination of data collected in the DSM‐IV field trial raised concerns that individuals with PDDs other than autism (i.e., Asperger’s syndrome, PDD‐NOS) and individuals with IQs in the normal range might be less likely to meet DSM‐5 criteria (McPartland, Reichow, & Volkmar, 2012). Other studies suggested that young children (Barton, Robins, Jashar, Brennan, & Fein, 2013) and females (Frazier et al., 2012) may be less likely to meet DSM‐5 criteria. More recent, large studies suggest that individuals currently meeting criteria for ASD will continue to do so according to DSM‐5 (Huerta, Bishop, Duncan, Hus, & Lord, 2012). There has been significant methodological variability among these studies in terms of data collection (e.g., re-analysis of historical data versus collecting new data using the proposed criteria) and in terms of symptom endorsement (e.g., clinical observation versus endorsement on one or more standardized assessment instruments), and these factors are demonstrated to influence ascertainment (Mazefsky, McPartland, Gastgeb, & Minshew, 2013). For these reasons, remaining questions will not be answered conclusively prior to the beginning process of implementing the new criteria. Given that most DSM‐5 research has taken place at major research centers, a key short‐term objective will be to understand the application of new criteria in smaller, purely clinical settings and in contexts in which the diagnostic criteria set itself will be employed as a checklist without reliance on standardized assessment measures.

    When the final criteria were published in May, the criteria set included a note that was not present in the posted draft criteria sets. This note states that a diagnosis of DSM‐5 ASD should be applied to individuals with well‐established DSM‐IV diagnoses on the autism spectrum. Given the extremely recent publication of the DSM‐5, this addition has not yet been examined in research studies or extensively discussed in popular media; however, initial impressions suggest that it will resolve several ongoing concerns and present interesting questions for the implementation and carrying forward of DSM‐5 criteria. By pre‐qualifying individuals with a DSM‐IV diagnosis, this “DSM‐ IV note” temporarily assuages concerns about changes in the prevalence of ASD wrought by the change in diagnostic criteria. The existing population of individuals with ASD will continue to meet criteria and, consequently, remain entitled to extant clinical, medical and educational services. Many stakeholders had also questioned whether publication of DSM‐5 criteria could lead to mandated diagnostic updates; this will also clearly not be the case. The effects of the note will, of course, only apply to individuals who have already been evaluated. Any potential changes attributable to the revised symptom set would emerge more gradually as children are born or age into a diagnostic system based on DSM‐5.

    The note also raises several interesting questions for clinicians to consider in the coming years. How will it apply to children with well‐established DSM‐IV diagnoses who make sufficient progress to no longer meet threshold for either criteria set? It will necessitate establishment of guidelines for the regularity of re‐evaluation and transition to DSM‐5 criteria within the lifespan of individuals. The note will also extend a period of taxonomic heterogeneity in the form of individuals concurrently in the service system with diagnoses based on distinct systems of classification. Long‐term research studies will need to devise strategies to manage individuals with similar phenotypic characteristics who may meet or fail to meet DSM‐5 diagnostic threshold based on whether they had previously been evaluated according to DSM‐IV criteria. As DSM‐5 is implemented, the field of intellectual and developmental disabilities and the broader community will learn more about its genuine impact in a wider variety of settings. Concerns about changes in prevalence should be reduced by built‐in mechanisms for diagnostic carryover from DSM‐IV, allowing for adaptation to this new diagnostic structure over time in terms of clinical evaluation, educational settings and care systems. These changes will be further complicated by trends among research funding agencies, such as the National Institute of Mental Health, to move away from categorical systems of classification towards a focus on transdiagnostic processes that correspond directly to biology. With the convergence of major changes in clinical classification and novel approaches to the organization of mental health research, the coming months and years offer unprecedented challenges and opportunities for clinical and research advances in autism spectrum disorders.

References

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders : DSM‐5 (5th ed.). Washington, DC: Author.

Barton, M., Robins, D., Jashar, D., Brennan, L., & Fein, D. (2013). Sensitivity and specificity of proposed DSM‐5 criteria for autism spectrum disorder in toddlers. Journal of Autism and Developmental Disorders, 43, 1184‐1195. doi: 10.1007/s10803‐013‐1817‐8 

Frazier, T. W., Youngstrom, E. A., Speer, L., Embacher, R., Law, P., Constantino, J., . . . Eng, C. (2012). Validation of proposed DSM‐5 criteria for autism spectrum disorder. Journal of the American Academy of Child and Adolescent Psychiatry, 51, 28‐40 e23. doi: 10.1016/ j.jaac.2011.09.021

Huerta, M., Bishop, S. L., Duncan, A., Hus, V., & Lord, C. (2012). Application of DSM‐5 criteria for autism spectrum disorder to three samples of children with DSM‐IV diagnoses of pervasive developmental disorders. American Journal of Psychiatry, 169, 1056‐1064. doi: 10.1176/appi.ajp.2012.12020276

Mazefsky, C. A., McPartland, J. C., Gastgeb, H. Z., & Minshew, N. J. (2013). Brief report: Comparability of DSM‐IV and DSM‐5 ASD research samples. Journal of Autism and Developmental Disorders, 43, 1236‐1242.

McPartland, J. C., Reichow, B., & Volkmar, F. R. (2012). Sensitivity and specificity of proposed DSM‐5 diagnostic criteria for autism spectrum disorder. Journal American Academy Child Adolescent Psychiatry, 51(4), 368‐383. doi: 10.1016/j.jaac.2012.01.007