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Autistic
Spectrum Disorders. Changes in the
California Caseload. An Update: 1999
Through 2002. California Department of
Developmental Services, April 2003.
PDF of report.
The California
Department of Developmental Services (DDS)
has just released an update of their
1999 report, which is an
accounting of the number of state residents
registered with the agency who have a
classification of autism. They document
continuing increases in individuals with
autism, with the number increasing 97
percent from 1998 through 2002.
Although the
California DDS update underscores the
undeniable fact that many more individuals
have autism spectrum disorders (ASDs) than
previously believed, in my opinion it is
still very difficult to determine to what
extent these increases are due to changes in
approaches to diagnosis and classification.
Because only those individuals with an
autistic disorder classification, and not
those with other ASDs, are eligible to
receive DDS services in California,
there may be pressure on those with other
ASDs to obtain an autistic disorder
classification. The proportion of
individuals in the California DDS system
with an autism classification and who did
not have any indication of mental
retardation has increased from 20 percent in
1987 to over 50 percent in December of 2002. |
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Lingam R,
Simmons A, Andrews N, Miller E, Stowe J,
Taylor B. Prevalence of autism and
parentally reported triggers in a north east
London population. Archives of Disease
in Childhood 2003; 88(8):666-670.
PubMed abstract.
Also see:
O'Neil. Patterns: Autism Cases Level Off in
Britain.
New York Times,
July 29, 2003.
Children born from
1979-1998 in five northeast London districts
were identified. The prevalance of autism
(including autistic disorder and pervasive
developmental disorder - not otherwise
specified) increased for each year of birth
until 1991, then leveled off to about 2.6
per 1,000 live births. The average age at
diagnosis decreased during this same time.
This is the
first epidemiologic report suggesting that
the prevalence of autism may be leveling off
after having increased for several years.
The findings are provocative, but are based
on a statistical model that uses past data
on children's ages at diagnosis to predict
numbers of children in more recent birth
cohorts likely to be diagnosed at older
ages. There is no a priori reason to
believe that this type of model would
artificially suggest a leveling off of
prevalence; nonetheless, another 5 to 10
years is needed to reveal whether reality
conforms to the model findings of Dr. Lingam
and colleagues. |
