Autism Spectrum Disorder (ASD) and the DSM-5
The newly updated version of the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5), sometimes referred to as "the bible of psychiatry," is flawed and inaccurate.
This may sound strange coming from a licensed psychologist but the truth is the various iterations of the DSM, originally published in 1952, have all been professionally criticized and scrutinized for the manner in which they define just what mental illness is and is not. Consider work on the DSM-5 began 14 years ago in 1999 and was just released to the public in May 2013. Consequently, it inherently lags behind current research by years just as most paper publications of its nature in the age of electronics. Furthermore, the DSM is produced by humans and is subsequently sure to be error-prone. Yet it represents a truly substantial, concerted attempt at classifying mental illness based on the best empirical data available. A more detailed evaluation is beyond the scope of this post but provides background for the many and varied opinions for why the DSM-5 committee chose to significantly restructure and redefine the criteria for the disorders previously referred to as Pervasive Developmental Disorders (PDD). Arguably, one of the most significant revisions to the DSM-5 is the removal of Asperger's Disorder from the classification system.
Research in the field of Autism Spectrum Disorders (ASD)
Research in the field of Autism Spectrum Disorders (ASD) has supported the idea that differentiating between children with and without ASD is a relatively reliable and valid exercise while identifying previous subtypes (Autistic Disorder, Asperger's, and PDD-NOS) was a more dubious and complex affair. Moreover, research suggests ASD exists along a continuum (or spectrum) rather than two specific, well-differentiated subtypes (Autism and Asperger's disorders). Finally, the disorder is no longer considered "pervasive" as many diagnosed individuals retain some domains of typically developing functioning. Hence, the DSM-5 now refers to the category as Autism Spectrum Disorder, acknowledging the wide range of presentations of people who may be on the spectrum. In fact, you won't find Pervasive Developmental Disorders in the DSM-5 as ASD is now housed under the category of Neurodevelopmental Disorders.
The DSM-5 committee
Additionally, the DSM-5 committee changed the inclusionary criteria for ASD in a significant and meaningful manner. Previously the three major discrete domains of impairment/delay for Autistic Disorder were social, communication, and stereotyped and repetitive behaviors. Now social and communication deficits have been reworded and combined into one major diagnostic cluster while stereotyped and repetitive behaviors form the second and final major cluster. The DSM-IV TR required symptoms be present before three years of age while the DSM-5 relaxed this criterion to "must be present in the early developmental period." Once considered a hallmark of Asperger's Disorder, deficits in pragmatic communication (i.e. the social rules of communication) now fall under a new disorder titled "Social (Pragmatic) Communication Disorder," which is included under Communication Disorders. Essentially, this part of the old PDD category has been pulled out from under the PDD umbrella (which no longer exists) and given a new name and home.
It remains to be seen exactly what long-term effects these changes will have on the number of children diagnosed with ASD and, more importantly, what services they may or may not receive as a consequence of the revisions. Rightly so, the removal of Asperger's Disorder is a fervently argued issue with many stakeholders. So while the controversy about Asperger's Disorder rages on we can always rest assured that another DSM should come around in a decade or so.