DSM IV and ICD 10 criteria

Rutter’s and Wing’s definition of autism was largely responsible for the introduction of autism as a distinct disorder in the DSM ( Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition )/ICD (International Classification of Diseases) systems of classification. At present, autism is conceptualized both in the DSM IV and the ICD as the main category in a group of disorders, the pervasive developmental or autism spectrum disorders (ASD), all of which are characterized by similar reciprocal social and communication deficits and rigid ritualistic interests beginning in early childhood. Other disorders in this category include Asperger syndrome, pervasive developmental disorder not otherwise specified (PDDNOS), Rett syndrome, and disintegrative disorder.

Patients with Asperger syndrome, as currently defined in the DSM IV, suffer from autistic social dysfunction but without mental retardation or language delay. Rett syndrome, caused by mutations in the MECP2 gene, is characterized by autistic features in one of its phases, whereas patients with disintegrative disorder develop normally in the first 4 to 5 years of life and then go through a period of disintegration. The last category, PDDNOS, is reserved for patients who are within the autistic spectrum but do not meet the threshold for any of the named disorders. For practical purposes, the term ASD often refers to autism, Asperger syndrome, and PDD NOS, excluding Rett syndrome and disintegrative disorder. Thus, although the diagnosis of classic autism is straightforward, the identification of the subtle forms of ASD and the delineation of its various subtypes can be particularly challenging. Partly because of this difficulty in separating the subtypes of ASD, the upcoming edition of the DSM is likely to introduce a paradigm shift in its approach to the classification of autism.

Proposed DSM V criteria

The fifth edition of the DSM (DSM V), scheduled to be published in 2013, is likely to introduce a single category of ASD and eliminate the subcategories. In brief, the draft of the DSM V has published on its Web site the following changes. First, the deficits of social interaction and communication that existed in DSM IV have now been merged into a single criterion of deficits in social communication and interaction. This is because, according to the draft criteria, deficits in communication and social behaviors are inseparable and more accurately considered as a single set of symptoms. The deficits must be clinically significant and persistent. These deficits should include marked impairment of both verbal and nonverbal communication used for social interaction; lack of social reciprocity (the degree of lack of reciprocity is not specified); and a failure to develop peer relationships at the appropriate developmental level. The second criterion consists of restricted repetitive interests shown by at least 2 of the following:

• 1.
  

  Stereotyped motor or verbal behaviors, or unusual sensory behaviors (unusual sensory behaviors were not included in the DSM IV)

  
  
• 2.
  

  Excessive adherence to routines and ritualized patterns of behavior

  
  
• 3.
  

  Restricted, fixated interests.

The third criterion states that the symptoms of autism must be present in early childhood (in contrast with the DSM IV, which required the symptoms to be present before 3 years of age), with the caveat that the symptoms may not become fully apparent until social demands exceed the limited capacities.

Thus, from DSM III (when autism was first introduced in the classificatory system) to the proposed DSM V, the approach to the classification of ASD seems to have gone full circle, beginning with lumping to splitting and back to lumping again. The rationale for eliminating Rett disorder and disintegrative disorder is presumably that they are now conceptualized as being more neurologic than psychiatric. Regarding the proposed elimination of Asperger syndrome (or Asperger disorder), according to the DSM V task force, the disorder is difficult to separate from autism with normal intelligence and has not been shown to be a valid category. However, a diagnosis does not have to be valid to be useful. Although there is no firm evidence that Asperger syndrome is distinct from autism, there is no denying that a diagnosis of Asperger syndrome can inform clinicians about the level of functioning, a pattern of behavior, and a likely outcome. Thus, the elimination of Asperger syndrome seems both unfortunate and premature.

Proposed DSM V criteria

The fifth edition of the DSM (DSM V), scheduled to be published in 2013, is likely to introduce a single category of ASD and eliminate the subcategories. In brief, the draft of the DSM V has published on its Web site the following changes. First, the deficits of social interaction and communication that existed in DSM IV have now been merged into a single criterion of deficits in social communication and interaction. This is because, according to the draft criteria, deficits in communication and social behaviors are inseparable and more accurately considered as a single set of symptoms. The deficits must be clinically significant and persistent. These deficits should include marked impairment of both verbal and nonverbal communication used for social interaction; lack of social reciprocity (the degree of lack of reciprocity is not specified); and a failure to develop peer relationships at the appropriate developmental level. The second criterion consists of restricted repetitive interests shown by at least 2 of the following:

• 1.
  

  Stereotyped motor or verbal behaviors, or unusual sensory behaviors (unusual sensory behaviors were not included in the DSM IV)

  
  
• 2.
  

  Excessive adherence to routines and ritualized patterns of behavior

  
  
• 3.
  

  Restricted, fixated interests.

The third criterion states that the symptoms of autism must be present in early childhood (in contrast with the DSM IV, which required the symptoms to be present before 3 years of age), with the caveat that the symptoms may not become fully apparent until social demands exceed the limited capacities.

Thus, from DSM III (when autism was first introduced in the classificatory system) to the proposed DSM V, the approach to the classification of ASD seems to have gone full circle, beginning with lumping to splitting and back to lumping again. The rationale for eliminating Rett disorder and disintegrative disorder is presumably that they are now conceptualized as being more neurologic than psychiatric. Regarding the proposed elimination of Asperger syndrome (or Asperger disorder), according to the DSM V task force, the disorder is difficult to separate from autism with normal intelligence and has not been shown to be a valid category. However, a diagnosis does not have to be valid to be useful. Although there is no firm evidence that Asperger syndrome is distinct from autism, there is no denying that a diagnosis of Asperger syndrome can inform clinicians about the level of functioning, a pattern of behavior, and a likely outcome. Thus, the elimination of Asperger syndrome seems both unfortunate and premature.

Diagnostic criteria and prevalence

One result of the changes in the diagnostic criteria has been the large increase reported in recent years in the prevalence of autism. When first described, autism was regarded as a rare condition affecting no more than 4 per 10,000; however, it is now much more common, occurring in at least 1 out of every 100 children. For example, a recent South Korean study reported that 2.6% of children aged 7 to 12 years meet the diagnostic criteria of ASD. Autism is no longer regarded as a single entity but as a collection of disorders grouped together as ASD. The condition described by Kanner, though uncommon, was not difficult to recognize. Children with autism typically show stereoptypic behaviors, perhaps repeating words or sentences, preoccupied with routines and rituals, lost in a world of their own, often withdrawn and aloof. However, children with suspected ASD, although common, are also difficult to identify because they often present with a range of deficits ranging from the most severe to the almost invisible. The distinction between autism/autistic disorders and ASD/other psychiatric disorders often seems vague and ill defined.

ASD in primary care

Because most children with ASD are first seen not by the specialist but by pediatricians and family practitioners, this article synthesizes the findings of recent studies dealing with the presentation and diagnosis of ASD in primary care and its distinction from other common psychiatric disorders of childhood. However, the ability of pediatricians to make this diagnosis depends not only on their training and background but also on the time they have at their disposal. Few pediatricians have enough time to screen for this condition. For example, in a mail survey of pediatricians, only about 8% endorsed screening for ASD. Although a significant number of the responders reported that they were not familiar with the screening procedures, others reported that they did not have enough time to conduct the assessments.