Autism diagnostic criteria
|
Autism Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Case Studies |
|
Autism diagnostic criteria On the Web |
|
American Roentgen Ray Society Images of Autism diagnostic criteria |
|
Risk calculators and risk factors for Autism diagnostic criteria |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Diagnostic Criteria
When the rising prevalence of autism spectrum disorders sparked research in the late 1990s, medical opinion initially attributed the increase to improved diagnostic screening or changes in the definition of autism. In 1994, the fourth major revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) was published with updated criteria for the diagnosis of autism and autism spectrum disorders.[1]
Autism is defined in the DSM-IV-TR as exhibiting at least six symptoms total, including at least two symptoms of qualitative impairment in social interaction, at least one symptom of qualitative impairment in communication, and at least one symptom of restricted and repetitive behavior.
Professional medical associations, including the American Academy of Pediatrics, say that this revision was an important factor in increasing the apparent prevalence of autism and a 2005 study by Mayo Clinic researchers found increases in autistic spectrum disorder diagnoses followed the revisions in DSM criteria and changes in funding for special education programs.[2]
An increased awareness of autistic spectrum disorders by parents and pediatricians may have also led to increased reporting of Autism due to 'case substitution', which occurs when children with other disorders are identified as autistic.[3] This misdiagnosis may occur for several reasons including an increase in government funding for care of children diagnosed as autistic, but not for children with a similar degree of disability and need. If this is occurring, it means that children who in the past would probably have been diagnosed as having a learning disability or a psychiatric disorder, or not diagnosed at all, are recorded as cases of autistic spectrum disorder.[4]
Children who are not primarily autistic, e.g. those with Fragile-X Syndrome (with characteristics that fit the criteria for autism) and even Down's Syndrome may have the diagnostic group with the best funding assigned. Dr. Fred Volkmar, a Yale University autism researcher, has said that "diagnostic substitution" was prompted by better services for autism.[5]
Care should be exercised when attempting to determine whether a person with autism is "high functioning" or "low functioning" based on an IQ score since it is sometimes difficult to measure IQ in autistic persons accurately using standard measurement instruments. The amount of language processing necessary on the tests and the large quantity of verbal instructions involved in the testing process even on the "non-verbal" portion of standard intelligence measures can produce a misleadingly low score. There can be a significant difference between an autistic person's measured IQ scores when comparing standard testing methods and a truly non-verbal method such as the Leiter-R.
A diagnosis of high-functioning autism exists in neither the DSM-IV-TR nor the ICD-10, which have diagnoses of autistic disorder and childhood autism respectively. Analogous to high-functioning when applied to schizophrenia and other psychiatric disorders, the term high-functioning autism started out as a shorthand to describe diagnosed autistic individuals who could nevertheless speak and carry on with many day-to-day activities like eating and dressing independently. Low-functioning autism was the conceptual opposite. Researchers then began using high-functioning autism as a quasi-diagnostic label itself, along with low-functioning autism and sometimes also Asperger's Syndrome, to distinguish relative levels of adaptation and development.
There is some evidence that the label has wrongly become a catch-all diagnosis for badly-behaved children. In 2000 in the UK, the lead clinician and autism specialist at Northgate and Prudhoe NHS Trust in Morpeth, Dr Tom Berney, published a paper commenting on this. He wrote in the prestigious British Journal of Psychiatry:- "There is a risk of the diagnosis of autism being extended to include anyone whose odd and troublesome personality does not readily fit some other category. Such over-inclusion is likely to devalue the diagnosis to a meaningless label."
References
- ↑ Tidmarsh L, Volkmar FR (2003). "Diagnosis and epidemiology of autism spectrum disorders". Can J Psychiatry. 48 (8): 517–25. PMID 14574827.
- ↑ Barbaresi WJ, Katusic SK, Colligan RC, Weaver AL, Jacobsen SJ (2005). "The incidence of autism in Olmsted County, Minnesota, 1976-1997: results from a population-based study". Arch Pediatr Adolesc Med. 159 (1): 37–44. doi:10.1001/archpedi.159.1.37. PMID 15630056.
- ↑ Shattuck PT (2006). "The contribution of diagnostic substitution to the growing administrative prevalence of autism in US special education". Pediatrics. 117 (4): 1028–37. doi:10.1542/peds.2005-1516. PMID 16585296. Lay summary (2006-04-03).
- ↑ Pettus A (2008). "A spectrum of disorders". Harv Mag. 110 (3): 27–31, 89–91.
- ↑ "Uncovering autism's mysteries: Is there more autism? Or just a new definition?". Associated Press. 2003-03-02. Retrieved 2007-12-30.
'Autism is kind of a fashionable diagnosis,' Volkmar said. 'Everybody's interested in getting better services.'