| Autism (incidence) |
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See Autism for general information about autism.
The reported incidence of autism varies considerably between countries and has shown large changes in limited time periods. There is uncertainty about the extent to which changes noted in the mid 1990's are accounted for by a change in the number of cases rather than by changed definitions, screening, improved recording and more frequent diagnoses including artifacts due to service provision. __TOC__ BACKGROUND The first diagnoses of autism were made in 1943 by psychiatrist Dr. Leo Kanner of the Johns Hopkins Hospital in Baltimore. Since then, the numbers diagnosed with autism have steadily increased. Data recording became more organised in the developed world in the 1990's. The organisation of information in general, and of interest and action groups became much easier, and individual paticipation more common in the latter half of the decade, after the introduction of the Web in 1993. Although diagnoses related to autism have increased, public health organizations and researchers have not yet determined the relative extents to which different aspects contribute to this Incidence National Autistic Society :
The increase in the recorded prevalence of autism has led to several new treatment programs, advocacy groups and support programs. Attempts in the US and UK to sue vaccine companies may have also increased case-reporting Summary item in "Overlawyered archive" . NEW DIAGNOSTICS When the rising prevalence of autism spectrum disorders sparked research in the late 1990's, the medical establishment primarily attributed the increase to improved diagnostic screening or changes in the definition of autism. In , say that this revision was an important factor in increasing the apparent prevalence of autism and a 2005 study by Mayo Clinic researchers found sharp increases in autism diagnoses followed the revisions in DSM criteria and changes in funding for special education programs. {Link without Title} . Some of the apparent increase might reflect increased awareness of autistic disorders by parents and pediatricians. The introduction of central funding for children diagnosed as autistic, but not for children with a similar degree of disability and need encourages ''case-substitution'' which does appear Am. Assoc. paed. Case substitution accounts for some of the increase in reported incidence to have occurred. 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 and it is possible that such misdiagnoses were more common in the recent past. 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.[http://edition.cnn.com/2003/HEALTH/conditions/03/02/autism.ap/ CNN report Dr Fred Volkmar, an autism researcher from Yale said "Autism is a kind of fashionable diagnosis". INCIDENCE IN SUB-GROUPS There have been suggestions that the incidence of autism may vary amongst particular groups defined by occupation. Changes that made travel and communication easier, and the growth of the technological industries during the past decade, have been suggested as means for increase in the proportion of couples likely to produce an autistic child. Parental type BBC report Simon Baron-Cohen believes that "it has become easier for systemizers to meet each other, with the advent of international conferences, greater job opportunities and more women working in these fields." Assortative mating has not been demonstrated in humans. The spouses of identical twins tended to find the other twin annoying rather than attractive.[http://www.int-pediatrics.org/PDF/Volume%2017/17-1/pd%2060-61%20mearns.pdf Mearns, Int. Paed. autistic individuals have a higher proportion of engineers as close family members than the rest of the population. Speculation on job choice and phenotype.. AREAS WITH A GENERAL PATTERN OF INCREASE Australia The Australian Education Department reported a 276 percent rise in students with autism spectrum disorder between 2000 and 2005 . Number of disabled students soars Sydney Children's Hospital Japan |
| "New cases" vs Incidence |
New cases could reasonably include older people newly diagnosed, and immigrants. Incidence is more precise and technical. This is another area that makes these statistics difficult. |
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