Asperger Syndrome Revisited
The removal of Asperger’s
disorder (Asperger syndrome) as a separate diagnostic category from the fifth
edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5)
has been widely publicized. The new DSM-5 category of autism spectrum
disorder (ASD), which subsumes the previous DSM-IV diagnoses of autistic
disorder (autism), Asperger’s disorder, childhood disintegrative disorder, and pervasive developmental disorder
not otherwise specified (PDD-NOS), reflects the scientific consensus that
symptoms of the various DSM-IV subgroups represent a single continuum of
impairment that varies in level of severity and need for support.
An important feature of
the DSM-5 criteria for ASD is a change from three symptom domains (triad)
of social impairment, communication deficits and repetitive/restricted
behaviors, interests, or activities to two domains (dyad); 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 language deficits are neither universal in
ASD, nor should they be considered as a defining feature of the diagnosis. The
criteria also feature dimensions of severity that include current levels of language
and intellectual functioning as well as greater flexibility in the criteria for
age of onset and addition of symptoms not previously included in the DSM-IV such
as sensory interests and aversions.
DSM-IV Criteria in Practice
Problems in applying the DSM-IV
criteria were a key consideration in the decision 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 DSM-IV 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 criteria for
Asperger’s disorder to also meet the criteria for autistic disorder.
Treatment and Outcome
Another important consideration
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 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 DSM-5 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 DSM-5 criteria for ASD
is that every individual who has significant “impairment” in
social interaction and communication, and restricted and repetitive behavior or interests should
meet the diagnostic criteria for ASD. Because language impairment/delay is not a necessary
criterion for diagnosis, 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, now meet the criteria for ASD. Specifiers are used to indicate level of severity and "without accompanying intellectual impairment and language impairment."
The DSM-5 criteria for
ASD have created significant controversy over concerns that it would exclude
many individuals currently diagnosed with Asperger syndrome and PDD-NOS, and
thus make it difficult for them to access services. However, recently published
field trials suggest that the revisions actually increase the reliability of
diagnosis, while identifying the large majority of those who would have been
diagnosed under the DSM-IV-TR. Of the small numbers who were not included, most
received the new diagnosis of “social communication disorder.” Moreover, the
accuracy of non-spectrum classification (specificity) made by DSM-5 was better
than that of DSM-IV, indicating greater effectiveness in distinguishing ASD
from non-spectrum disorders such as language disorders, intellectual
disability, attention-deficit/hyperactivity disorder (ADHD), and anxiety
disorders.
It is important to note that all individuals who have a DSM-IV
diagnosis on the autism spectrum, including those with Asperger syndrome and
PDD-NOS, will be able to retain an ASD diagnosis. This means that no one should
“lose” their diagnosis because of the changes in diagnostic criteria. According to DSM-5, individuals with a
well-established DSM-IV diagnosis of Autistic Disorder, Asperger’s Disorder, or
PDD-NOS should be given a diagnosis of ASD.
Those who have marked deficits in social communication, but whose
symptoms do not meet the criteria for ASD, should be evaluated for Social
(Pragmatic) Communication Disorder.
Conclusion
In conclusion, the DSM-5
category of autism spectrum disorder (ASD), 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's 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's 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 autism and that
intervention/treatment, course, and outcome were clinically different for each
disorder. While including Asperger’s Disorder under the DSM-5 category of ASD
will likely continue to require a period of transition and adjustment, this dimensional approach to diagnosis will likely result in more effective
identification, treatment, and research for individuals on the spectrum.
Key References & Further Reading
American Psychiatric
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Washington, DC: Author.
American Psychiatric
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(4th ed., text rev.). Washington, DC: Author.
American Psychiatric
Association (2013). Diagnostic and statistical manual of mental disorders
(5th ed.). Washington, DC: Author.
Attwood, T. (2006). The
complete guide to Asperger’s syndrome. London: Jessica Kingsley.
Carpenter, L. A., Soorya,
L. & Halpern, D. (2009). Asperger’s syndrome and high- functioning autism. Pediatric
Annals, 38, 30-35.
Eisenmajer, R., Prior, M.,
Leekam, S., Wing, L., Ong, B., Gould, J. & Welham, M. (1998)
Delayed Language Onset as
a Predictor of Clinical Symptoms in Pervasive Developmental Disorders. Journal
of Autism and Developmental Disorders, 28, 527–34.
Gillberg, C (2001).
Asperger’s syndrome and high functioning autism: Shared deficits or
different Disorders? Journal
of Developmental and Learning Disorders, 5, 79-94.
Howlin, P. (2003). Outcome
in high-functioning adults with autism with and without early language delays:
Implications for the differentiation between autism and Asperger syndrome. Journal
of Autism and Developmental Disorders, 33, 3–13.
Leekam, S., Libby, S.,
Wing, L., Gould, J. & Gillberg, C. (2000) Comparison of ICD-10 and Gillberg’s
criteria for Asperger syndrome. Autism, 4, 11–28.
Lord, C. et al. (2011). A
multisite study of the clinical diagnosis of different autism spectrum disorders.
Archives of General Psychiatry. doi:10.1001/archgenpsychiatry.2011.148
Macintosh, K., &
Dissanayake, C. (2006). Social skills and problem behaviors in school aged children
with high-functioning autism and Asperger’s disorder. Journal of Autism and
Developmental Disorders, 36, 1065–1076.
Macintosh, K.E., &
Dissanayake, C. (2004). Annotation: The similarities and differences between autistic disorder
and Asperger’s disorder: A review of the empirical evidence. Journal of
Child Psychology and Psychiatry, 45, 421–434.
Mayes, S., & Calhoun,
S. (2003). Relationship between Asperger syndrome and high functioning autism.
In M. Prior (Ed.), Learning and behavior problems in Asperger syndrome (pp.
15-34). New York: Guilford Press.
Mayes SD, Calhoun SL,
Crites DL (2001) Does DSM-IV Asperger’s disorder exist? Journal of Abnormal
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Ozonoff, S. (2000). The external validity of Asperger disorder: Lack of evidence
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Ozonoff, S., Dawson, G.,
& McPartland, J. (2002). A parent’s guide to Asperger syndrome and
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& Miller, J. N. (2000). DSM-IV-defined Asperger syndrome: Cognitive, behavioral
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Szatmari, P., Bryson, S.,
Duku, E., Vaccarella, L., Zwaigenbaum, L., Bennett, L. & Boyle, M.H. (2009).
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best practice guide to assessment and intervention for Asperger syndrome and
autism in schools. London: Jessica Kingsley Publishers.
Wilkinson, L. A. (Ed.) (2014). Autism spectrum disorder in children and adolescents: Evidence-based
assessment and intervention in schools. American Psychological Association
(APA): Washington, DC.
Wilkinson, L. A. (2017). A best practice guide to assessment and intervention for Asperger autism spectrum disorder in schools. London: Jessica Kingsley Publishers.
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disorders: Vol. 1. Diagnosis, development, neurobiology, and behavior (3rd
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