DSM-5: Rethinking Asperger's Disorder

The American Psychiatric Association’s recommendation to delete (remove) Asperger’s disorder as a separate diagnostic category from the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) has been widely publicized.  Specifically, DSM-5 Work Group members propose a new category of “autism spectrum disorder,” which subsumes the current diagnoses of autistic disorder (autism), Asperger’s disorder, childhood disintegrative disorder, and pervasive developmental disorder not otherwise specified (PDD-NOS). This new category reflects members’ conclusion that “a single spectrum disorder” better describes our current understanding of the neurodevelopmental disorders.

An important feature of the proposed criteria for autism spectrum disorder (ASD) is a change from three (autistic triad) to two domains; “social/communication deficits” and “fixated and repetitive pattern of behaviors.” Several social/communication criteria were merged to clarify diagnostic requirements and reflect research indicating that deficits in communication are “inseparable and more accurately considered as a single set of symptoms...”  Work Group members commented that language deficits are neither universal in ASD, nor should they be considered as a defining feature of the diagnosis.

DSM-IV Criteria in Practice

Problems in applying the current DSM criteria were a key consideration in the Work Group’s recommendation to delete Asperger’s disorder as a separate diagnostic entity. Numerous studies indicate that it is difficult to reliably distinguish between Asperger syndrome, autism, and other disorders on the spectrum in clinical practice (Attwood, 2006; Macintosh & Dissanayake, 2006; Leekam, Libby, Wing, Gould & Gillberg, 2000; Mayes & Calhoun, 2003; Mayes, Calhoun, & Crites, 2001; Miller & Ozonoff, 2000; Ozonoff, Dawson, & McPartland, 2002; Witwer & Lecavalier, 2008). For example, children with autism who develop proficient language have very similar trajectories and later outcomes as children with Asperger disorder (Bennett et al., 2008; Howlin, 2003; Szatmari et al., 2000) and the two are indistinguishable by school-age (Macintosh & Dissanayake, 2004), adolescence (Eisenmajer, Prior, Leekam, Wing, Ong, Gould & Welham 1998; Ozonoff, South and Miller 2000) and adulthood (Howlin, 2003). Individuals with Asperger disorder also typically meet the Communication criterion of autism, “marked impairment in the ability to initiate or sustain a conversation with others,” making it is possible for someone who meets the DSM-IV-TR criteria for Asperger’s disorder to also meet the criteria for autistic disorder.

Treatment and Outcome

Another important consider in the DSM proposal was response to treatment. Intervention research cannot predict, at the present time, which particular intervention approach works best with which individual. Likewise, data is not available on the differential responsiveness of children with Asperger’s disorder and high-functioning autism (HFA) to specific interventions (Carpenter, Soorya, & Halpern, 2009). There are no empirical studies demonstrating the need for different treatments or different responses to the same treatment, and in clinical practice the same interventions are typically offered for both autism and Asperger’s disorder (Wilkinson, 2010). Treatments for impairments in pragmatic (social) language and social skills are the same for both groups.

Application of the New Criteria

It’s important to remember that in the DSM, a mental disorder is conceptualized as a clinically important collection of behavioral and psychological symptoms that causes an individual distress, disability or impairment. The objective of the draft criteria is that every individual who has significant “impairment” in social-communication and restricted and repetitive behavior or interests (RRBI) should meet the diagnostic criteria for autism spectrum disorder. Language impairment/delay is not a necessary criterion for diagnosis of ASD. Therefore anyone who demonstrates severe and sustained impairments in social skills and restricted, repetitive patterns of behavior, interests, or activities in the presence of generally age-appropriate language acquisition and cognitive functioning, who might previously have been given a diagnosis of Asperger’s disorder, would now meet the criteria for the new category of ASD. The draft criteria would also feature dimensions of severity that include current levels of language and intellectual functioning. Additionally, the Work Group intends to provide detailed symptom examples suitable for all ages and language levels, so that ASD will not be overlooked in persons of average or superior IQ who are experiencing “clinical” levels of difficulty.

Conclusion

In conclusion, the DSM-V Work Group members’ proposal of a new category, “autism spectrum disorder,” which subsumes the current diagnoses of autistic disorder, Asperger’s disorder, childhood disintegrative disorder, and pervasive developmental disorder not otherwise specified (PDD-NOS), better describes our current understanding about the clinical presentation and course of the neurodevelopmental disorders. Conceptualizing autism as a spectrum condition rather than a categorical diagnostic entity is in keeping with the extant research suggesting that there is no clear evidence that Asperger’s disorder and high-functioning autism are different disorders. As Gillberg (2001) notes, the terms Asperger syndrome and high-functioning autism are more likely “synonyms” than labels for different disorders. Lord (2011) also comments that although there has been much controversy about whether there should be separate diagnoses, "Most of the research has suggested that Asperger syndrome really isn't different from other autism spectrum disorders." "The take-home message is that there really should be just a general category of autism spectrum disorder, and then clinicians should be able to describe a child's severity on these separate dimensions." Unfortunately, many individuals may have been advised (or assumed) that a diagnosis of Asperger’s disorder was separate and distinct from Autistic disorder and that intervention/treatment, course, and outcome were clinically different for each disorder. While including Asperger’s Disorder under the proposed category of “autism spectrum disorder” may well require a period of transition and adjustment, the proposed “dimensional” approach to diagnosis will likely result in more effective identification, treatment, and research for individuals on the spectrum.

The complete article and list of references are available at <On the Road to DSM-5: Rethinking Asperger’s Disorder>

A more detailed summary and discussion of the proposed draft revisions to DSM disorders and criteria are available at <http://www.dsm5.org>

© Lee A. Wilkinson, PhD