During the last decade the reported cases of autism and other illnesses related to brain development have dramatically increased not just in the U.S. but around the world. Scientists say the increase cannot be explained by genetics and they believe it's linked to the increase of toxic chemicals in the environment.
Dr. Martha Herbert is a pediatric neurologist at Massachusetts General Hospital. She's directing a large research study on toxic chemicals in the environment and their impact on brain development, including autism. "The genes load the gun," she said. "But the environment pulls the trigger."
For years, scientists have believed that autism was genetically based.
But Dr. Herbert believes environmental factors can either trigger or worsen the illness.
She says finding those elements early in life and changing them could determine the severity of the disease. "We have a system in the body called the detoxification system, detoxification is another variant. In detoxification you get rid of things that you don't want either your body's own waste products or things that get in which you don't want to have around," she said. "It can be air pollution, it can be plastics in the food, it can be pesticides that are in so many of our products."
Dr. Herbert's research involves babies, school age children and adults, with and without autism.
She is trying to find out how the brain becomes autistic and at what point.
She has been following Kenzie and Cooper, brothers who don't have autism. Like others in her study, she tests them regularly for toxic chemicals, brain imaging changes and developmental disorders.
"My personal commitment is to test and if it is true then to show that the influence of chemicals on the brain is not just during development but in your whole life," Dr. Herbert explained.
Dr. Herbert is not alone in looking at the environment.
Dr. Larry Silver is a Professor of Psychiatry at Georgetown University Medical Center in Washington. He has been researching learning disabilities for more than 40 years. He says he knows enough to be concerned about toxic chemicals in the environment. "We have increasing concern that the environmental toxins may be contributing to these disabilities and also to the increase in these disabilities," he said.
In the U.S. nearly 3 million people have been diagnosed with autism. While in 1994 one in every 1000 children was diagnosed with the disease, today there is one for every 110.
Jeff Sell at the Autism Society says numbers around the world are similar. "Genetics alone cannot explain that type of increase in prevalence," he said. Two of Sell's four children are autistic, even though there's no family history. "My boys both have high mercury levels, lead, pcvs," he added.
For many years, advocates for autism patients believed the disease is caused by vaccinations, especially the measles vaccine. But several studies found no link between vaccines and autism.
Now Sell and the Autism Society are pressing to update legislation on toxic chemicals. He says there are more than 82,000 chemicals being released into the environment, but there's good information on only 200.
He says we are damaging not only the human population, but the world we live in.
Story was narrated by Mil Arcega