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AUTISM EPIDEMIOLOGY
Gender differences
There is not a clear-cut ratio of incidence between males and
females. Studies have found much higher prevalence in males at the
high-functioning end of the spectrum, while the ratios appear to be closer
to 1:1 at the low-functioning end.[45] In addition, a study published in
2006 suggested that males over 40 are more likely than younger males to
parent a child with autism, and that the ratio of autism incidence in
males and females is closer to 1:1 with older fathers.[46]
Reported increase with time
The number of reported cases of autism increased dramatically over a
decade. Statistics in graph from the National Center for Health
Statistics.There was a worldwide increase in reported cases of autism over
the decade to 2006. There are several theories about the apparent sudden
increase.
Many epidemiologists argue that the rise in the incidence of autism in the
United States is largely attributable to a broadening of the diagnostic
concept, reclassifications, public awareness, and the incentive to receive
federally mandated services.[47] However, some authors indicate that the
existence of an as yet unidentified contributing environmental risk factor
cannot be ruled out.[48] On the other hand, a widely-cited pilot study
conducted in California by the UC Davis M.I.N.D. Institute (17 October
2002), reported that the increase in autism in California is real, even
after accounting for changes to diagnostic criteria.
The question of whether the rise in incidence is real or an artifact of
improved diagnosis and a broader concept of autism remains controversial.
Dr. Chris Johnson, a professor of pediatrics at the University of Texas
Health Sciences Center at San Antonio and co-chair of the American Academy
of Pediatrics Autism Expert Panel, sums up the state of the issue by
saying, "There is a chance we're seeing a true rise, but right now I do
not think anybody can answer that question for sure."
The answer to this question has significant ramifications on the direction
of research, since a real increase would focus more attention (and
research funding) on the search for environmental factors, while the
alternative would focus more attention to genetics. On the other hand, it
is conceivable that certain environmental factors (such as chemicals,
infections, medicines, vaccines, diet and societal changes) may have a
particular impact on people with a specific genetic constitution.
One of the more popular theories is that there is a connection between "geekdom"
and autism. This is hinted, for instance, by a Wired Magazine article in
2001 entitled "The Geek Syndrome", which is a point argued by many in the
autism rights movement. This article, many professionals assert, is just
one example of the media's application of mental disease labels to what is
actually variant normal behavior—they argue that shyness, lack of athletic
ability or social skills, and intellectual interests, even when they seem
unusual to others, are not in themselves signs of autism or Asperger's
syndrome. Others assert that children who in the past would have simply
been accepted as a little different or even labeled 'gifted' are now being
labeled with mental disease diagnoses. See clinomorphism for further
discussion of this issue.
Due to the recent publicity surrounding autism and autistic spectrum
disorders, an increasing number of adults are choosing to seek diagnoses
of high-functioning autism or Asperger's syndrome in light of symptoms
they currently experience or experienced during childhood. Since the cause
of autism is thought to be at least partly genetic, a proportion of these
adults seek their own diagnosis specifically as follow-up to their
children's diagnoses. Because autism falls into the pervasive
developmental disorder category, an individual's symptoms must have been
present before age seven in order to make a strict differential diagnosis.
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1
Terminology
2
History
3
Characteristics
Key Behaviors
Noted behaviors
Social development
Sensory system
Autism and blindness
Communication difficulties
Repetitive behaviors
Effects in education
4
DSM definition
5
Types of autism
Asperger's and Kanner's syndrome
Autism as a spectrum disorder
6
Epidemiology
7
Treatment
8
Causes
Physiology and Neurology
Genetic Component
9
Sociology
Community and politics
Culture
Autistic adults
Terminology
Autistic savants
References |
