A recent report by Lisa Croen, et al suggested that the
apparent rise in autism prevalance as evidenced by the
M.I.N.D. report using the CA Regional Centers’ data was in
fact explained by a shifting of diagnosis from MR to AU.
Twenty years ago, it would not be uncommon for children who had autism to be mislabeled by drs. and psyches who may not be familiar enough with autism to recognize what they were observing and to fall back upon the more generic label MR from unknown couses.
Croen pointed out that using two years of reference, 1987
and 1994, data showed MR had declined as a diagnosis by
nearly the same margin that autism had increased. Some
“experts” hailed this report as proof that autism had not
really increased, just our ability to recognize it, notably
Eric Fombonne who goes so far as to suggest that many of
today’s autistic kids are not autistic at all, just labeled
as such so parents can get services for children who
otherwise would not qualify for them.
M.I.N.D. took offense at this, despite the fact that their
report was never intended to demonstrate prevalance as
their data was not referenced to populations, but just
incidence, which is mor of a factor of time. They went
back and reviewed two years, 1987 and 1998 to see if the
theory of shifting diagnosis could account for some or all
of the apparent rise. What they found was that the
professional diagnosies of children in both years had about
the same degree of accurac, better than 90% (they also
found that migration was not a major factor since better
than 90% of the children in both reference years were also
native born Californians.)
The report linked below goes further, and analyzes the
Croen report’s survey and reporting techniques and shows
how this report was in itself misleading. While this by no
means represents proof positive that the increase in autism
in CA (among other places) is real, it does remove one more argument that it is NOT real.
http://home.sprynet.com/%7Eschafer/lib/Blaxill.Baskin.Spitzer.pdf