Monday, December 10, 2012

DSM-5 ASD Criteria Unlikely to Exclude Many Individuals

The American Psychiatric Association voted to approve the revised fifth edition of its Diagnostic and Statistical Manual of Mental Disorders (DSM-5) on December 1, 2012. The manual is used by clinicians nationwide to diagnose mental health conditions and will be published in spring 2013. Among other changes, the revision introduces fundamental changes in the diagnosis of autism. It collapses the previously distinct autism subtypes, including autistic disorder, Asperger’s disorder (syndrome), and pervasive developmental disorder-not otherwise specified (PDD-NOS) into a single unifying diagnosis of autism spectrum disorder (ASD). Further, the current DSM-IV-TR three symptom domains (triad) of social impairment, communication deficits and repetitive/restricted behaviors, interests, or activities will be replaced with two domains, social communication impairment and repetitive/restricted behaviors or interests. Changes also include greater flexibility in the criteria for age of onset and addition of symptoms not previously included in the DSM-IV-TR such as sensory interests and aversions.
The new DSM-5 criteria for ASD have created significant controversy with predictions that it would exclude many individuals from an autism diagnosis and thus make it difficult for them to access services. Critics suggest that the new criteria are too narrow and will leave out a large number of people currently diagnosed with Asperger syndrome and PDD-NOS). However, early studies suggest that fears that many individuals will be excluded appear to be largely unfounded. For example, a recently published field trial suggests that the revisions 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.” The DSM-5 criteria also proved highly reliable, meaning that two different clinicians using them were likely to diagnose the same person with the same disorder.
A comprehensive study published in the American Journal of Psychiatry also lends support to application of the DSM-5 criteria. Researchers evaluated the new criteria in children with DSM-IV diagnoses of pervasive developmental disorders (PDD) and non-PDD diagnoses and found that the DSM-5 criteria identified a majority of children with clinical DSM-IV diagnoses. The study used three data sets from 4,453 children with DSM-IV clinical PDD diagnoses and 690 with non-PDD diagnoses (e.g., language disorder).  Items from a parent report measure of ASD symptoms (Autism Diagnostic Interview–Revised) and a clinical observation instrument (Autism Diagnostic Observation Schedule) were matched to DSM-5 criteria and used to evaluate the sensitivity (percentage individuals with ASD who are correctly identified) and specificity (percentage of individuals without ASD who are correctly identified) of the DSM-5 criteria and current DSM-IV criteria when compared with clinical diagnoses. According to the results, the majority of children with clinical diagnoses of PDD met the DSM-5 ASD criteria according to item scores on the Autism Diagnostic Interview–Revised and the Autism Diagnostic Observation Schedule. Application of the DSM-5 criteria demonstrated adequate sensitivity across all groups, On the basis of either parent report or clinical observation, DSM-5 sensitivity ranged from 0.97 to 0.99 for any PDD. Overall, the sensitivity values of the DSM-5 and DSM-IV criteria were comparable. 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, and anxiety disorders. The researchers conclude that “Based on symptom extraction from previously collected data, our findings indicate that the majority of children with DSM-IV PDD diagnoses would continue to be eligible for an ASD diagnosis under DSM-5. Additionally, these results further suggest that the revisions to the criteria, when applied to records of children with non-PDD diagnoses, yield fewer misclassifications.”
Autism researcher Geraldine Dawson, chief science officer for Autism Speaks, commented that although the new criteria appear to be effective, it will be critical to monitor so that children don't lose services. According to an open letter from Dawson, “We are reassured that the DSM-5 committee has stated that all individuals who currently have a diagnosis on the autism spectrum, including those with Asperger syndrome, will be able to retain an ASD diagnosis. This means that no one with a current diagnosis on the autism spectrum should “lose” their diagnosis because of the changes in diagnostic criteria. Also, the committee has stressed that the new DSM-5 criteria represent a “living document in which changes can and likely will be made as new studies are conducted.” “Today, after careful consideration, we are acknowledging the APA’s approval of the DSM-5 with cautious optimism” she said.
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.
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

Lee A. Wilkinson, PhD, CCBT, NCSP is author of the award-winning book, A Best Practice Guide to Assessment and Intervention for Autism and Asperger Syndrome in Schools, published by Jessica Kingsley Publishers. He is also editor of a recent volume in the APA School Psychology Book Series, Autism Spectrum Disorder in Children and Adolescents: Evidence-Based Assessment and Intervention in Schools and author of the new book, Overcoming Anxiety and Depression on the Autism Spectrum: A Self-Help Guide Using CBT.

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