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Autism spectrum disorders (ASD), also called autism spectrum conditions (ASC) or the autism spectrum, with the word autistic sometimes replacing autism, are a spectrum of psychological conditions characterized by widespread abnormalities of social interactions and communication, as well as severely restricted interests and highly repetitive behavior.

Autism is one of the five autism spectrum disorders. Of the other four autism spectrum disorders, Asperger's syndrome is closest to autism in signs and likely causes; Rett syndrome and childhood disintegrative disorder share several signs with autism but may have unrelated causes; finally, pervasive developmental disorder not otherwise specified (PDD-NOS) is diagnosed when the criteria are not met for a more specific disorder. Unlike autism, Asperger's has no significant delay in language development.

The terminology of autism can be bewildering, with autism, Asperger's, and PDD-NOS sometimes called the autistic disorders, whereas autism itself is often called autistic disorder, childhood autism, or infantile autism. ASD in turn is a subset of the broader autism phenotype (BAP), which describes individuals who may not have ASD but do have some autistic-like traits, such as avoiding eye contact.

One review estimated a prevalence of at least 1.3 per 1,000 for autism and 6.0–6.5 per 1,000 for ASD; PDD-NOS was the vast majority of ASD, Asperger's was about 0.3 per 1,000 and the atypical forms childhood disintegrative disorder and Rett syndrome were much rarer.

Autistic traits

Behaviorally, certain characteristics identify the autism spectrum. The type, severity and/or number of autistic traits present determines the severity of autism in the individual. These autistic traits may be beneficial for some disciplines like science, mathematics, engineering and computer programming. Some autistic individuals might show a marked proficiency in rote memorization which may help learn the foundation of these subjects; however, the exceptionally good aptitude (in these subjects) of high functioning autistic spectrum persons may be due to their ability to readily identify patterns and apply them consistently to new situations outside of established knowledge or teaching. These savant skills, although popularly considered to be a major part of autistic disorders, are evident only in a small fraction of autistic individuals, with estimates of the fraction ranging from 0.5% to 10%.

Diagnostic criteria and techniques

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. 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.

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. 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 different condition, or not diagnosed at all are recorded as new cases of autistic spectrum disorder. Possible alternate diagnoses include mental retardation, learning disability and childhood schizophrenia. High-functioning autistic children are sometimes misdiagnosed ADHD. 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.

ADHD and autism

Some research suggests a possible genetic and behavioral connection between ADHD and autism.

References

1. World Health Organization (2006). "F84. Pervasive developmental disorders". International Statistical Classification of Diseases and Related Health Problems (10th ed. (ICD-10) ed.). {{cite book}}: |access-date= requires |url= (help); External link in |chapterurl= (help); Unknown parameter |chapterurl= ignored (|chapter-url= suggested) (help)
2. Lord C, Cook EH, Leventhal BL, Amaral DG (2000). "Autism spectrum disorders" (PDF). Neuron. 28 (2): 355–63. doi:10.1016/S0896-6273(00)00115-X. PMID 11144346.{{cite journal}}: CS1 maint: multiple names: authors list (link)
3. American Psychiatric Association (2000). "Diagnostic criteria for 299.80 Asperger's Disorder (AD)". Diagnostic and Statistical Manual of Mental Disorders (4th ed., text revision (DSM-IV-TR) ed.). ISBN 0890420254. {{cite book}}: |access-date= requires |url= (help); External link in |chapterurl= (help); Unknown parameter |chapterurl= ignored (|chapter-url= suggested) (help)
4. Freitag CM (2007). "The genetics of autistic disorders and its clinical relevance: a review of the literature". Mol Psychiatry. 12 (1): 2–22. doi:10.1038/sj.mp.4001896. PMID 17033636.
5. Piven J, Palmer P, Jacobi D, Childress D, Arndt S (1997). "Broader autism phenotype: evidence from a family history study of multiple-incidence autism families" (PDF). Am J Psychiatry. 154 (2): 185–90. PMID 9016266.{{cite journal}}: CS1 maint: multiple names: authors list (link)
6. Fombonne E (2005). "Epidemiology of autistic disorder and other pervasive developmental disorders". J Clin Psychiatry. 66 (Suppl 10): 3–8. PMID 16401144.
7. Treffert DA (2007). "Savant syndrome: an extraordinary condition—a synopsis: past, present, future". Wisconsin Medical Society. Retrieved 2007-09-19.
10. 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". Archives of pediatrics & adolescent medicine. 159 (1): 37–44. doi:10.1001/archpedi.159.1.37. PMID 15630056.{{cite journal}}: CS1 maint: multiple names: authors list (link)
11. Am. Assoc. paed. Case substitution accounts for some of the increase in reported incidence
14. CNN report Dr Fred Volkmar, an autism researcher from Yale said "Autism is a kind of fashionable diagnosis".

External links

• Template:Dmoz
• CDC's "Learn the Signs. Act Early.” campaign - Information for parents on early childhood development and developmental disabilities such as autism
• Autism Spectrum Disorders (Pervasive Developmental Disorders)
• Autism Spectrum Disorder Supporting family members on the spectrum
• Autism Spectrum Disorders from ScienceDaily - Latest research news on autism spectrum disorders. Includes searchable archives
• Attention deficit hyperactivity disorder and autism

• Autism