Causes of Autism: Recent Findings

Growing Consensus Among Scientists:

"In autism there are lots of opinions and very little data," says Lisa Croen, Ph.D. Research Scientist in the Division of Research at Kaiser Permanente in Northern California. In the past few years, however, some consensus has emerged on at least a few new pieces of the puzzle. As the research progresses, it will be easier to see the relationships among findings -- and to tease out the appropriate treatments for each individual on the autism spectrum.

There Is More Than One "Autism":

About 25% of autistic people have digestive issues; 25% have seizure disorders; many have sleep problems. Recent findings suggest that the many different symptoms may actually indicate many different causes -- and thus many different "autisms." A massive study now underway at UC Davis's M.I.N.D. Institute is in the process of separating out different autistic phenotypes with the hope that this information will speed better understanding of causes and treatments.

Autism has a genetic component:

Autism is hereditary, in that children with autistic people in their family are more likely than other children to be autistic.

Researchers are well on the way to finding genes that relate to autism -- but the jury is still out regarding exactly how such genes might function to create autistic symptoms. Sophia Colamarino, Science Program Director at Cure Autism Now, explains,"We’re talking about genes because they allow us to understand the biological origins of the problem."

There is a Relationship Between Autism and Brain Structure:

Recent brain studies show that autistic brains grow at an unusual rate between age 1 and 2, and then slow again to a normal rate of growth. Some imaging studies suggest that certain areas of the brain are larger than is typical. Research is ongoing to determine whether these differences in brain structure cause autism, are caused by autism, or are co morbid with autism and caused by something else.

There Is a Relationship Between Autism and Brain Activity:

Recent brain imaging studies show that autistic people and typically developing people do not use their brains in the same way. Autistic people do not use their brains to "daydream" in the same way as most people, nor do they process information about faces in the same way.

So far, while we know that this information is true, we don't know what causes these differences -- or whether these differences somehow cause autistic symptoms.

There Is a Relationship Between Autism and Brain Chemicals:

Chemicals in the brain transmit signals which allow the brain to function normally. Sophia Colamarino explains: "Nerve cells communicate using electrochemical signals; there is evidence from many different domains that the ability of the brain to transfer information may be defective." An understanding of which transmitters are problemmatic may lead to effective treatments.

Genes Probably Interact with Environmental Factors:

It is likely that genetics and environmental factors interact to cause autism. As yet, there is no proof of which environmental or genetic factors are to blame. Says Dr. Croen, autism "You need some kind of genetic susceptibility; then you have to be exposed to something which is elusive at the moment. This would be the impetus that sends you into autism."

No One Factor Causes Autism:

It is unlikely that any one factor -- vaccines, foods, or environmental toxins -- is the cause of autism. "To find clues about the cause," says Dr. Croen, "we have to do really large studies to look at different configurations of co-morbidities… see what’s unique about each separate group." New research will be address the questions "How do these circles overlap? What is the common thread?"

References:

Interview: Dr. Lisa Croen, Ph.D. Research Scientist in the Division of Research at Kaiser Permanente in Northern California

Interview: Sophia Colamarino Science Program Director at Cure Autism Now

Organization for Autism Research