Skip to content

Autism Spectrum Disorders Health Center

New Intensity to Debate Over Autism Cause

Parents and Researchers Grapple With Claims That Autism Is Linked to Thimerosal in Vaccines
Font Size
A
A
A

continued...

Oft-Cited Study Questioned

A 2002 pilot study by the MIND Institute of the University of California, Davis, looked at the issue of whether autism rates are really getting higher -- or whether we're just getting better at finding kids with autism.

Study leader Robert Byrd, MD, MPH, associate professor of clinical pediatrics at the University of California, Davis, says the study data suggest that any "loosening" of diagnostic criteria had no effect on autism rates in California. This study, despite shortcomings Byrd readily admits, is widely cited as proof that the autism epidemic is real.

The MIND study compared autistic kids born in 1982-1985 to kids born in 1993-1995. Using the current criteria for diagnosis, Byrd's team found that the more recently diagnosed kids were nearly as severely autistic as those in the earlier group.

"In both groups, they on average aren't just barely meeting the threshold to be called autism -- they are almost double the threshold," Byrd tells WebMD.

MIND Institute executive director Robert Hendren, DO, also defends the study findings.

"This study is just one data point that exists, not the final word on the subject," Hendren says. "But based on this study, we say the increase in autism incidence is not a matter of changing diagnostic practices."

Gernsbacher says the findings are based on backward reasoning. Her main point: The study uses the current, looser definition of autism to look at children diagnosed under a more strict definition. Then it mistakenly concludes that since those kids meet the looser definition, the new definition made no difference.

A 2005 study by Craig J. Newschaffer, PhD, and colleagues at the Johns Hopkins Center for Autism and Developmental Disabilities Epidemiology shows "a drastic increase in the prevalence of the autism classification." The study concludes that it's important to find out how much of this is due to a change in diagnosis and how much is due to "real changes in risk."

Collision: Autism Rise, Vaccine Concern

Fact: Nobody knows what causes autism. Nobody is even sure whether autism in all its different forms has one cause or many. Since autism runs in families, nearly everyone agrees there's a genetic link. Might that link be something that makes some people especially sensitive to something in the environment?

1 | 2 | 3 | 4 | 5 | 6 | 7

Today on WebMD

girl at window
Symptoms within the first 2 years of a child’s life.
boy playing a violin
How is this condition similar to autism?
 
toddler blinking
Learn about the 5 types of PDD.
preschool age girl sitting at desk
What causes this rare form of autism?
 
High Functioning Autism And Asperge Syndrome
Article
Gluten Free Diet Slideshow
Article
 
Dealing With Autism A Familys Journey
Article
Vaccine and needle
VIDEO
 
little boy walking in road
Article
Mother hugging teenage son
Article
 
Understanding Rett Syndrome
Article
Home Care Tips
Article