The ongoing debate about the causes of autism will long continue, and “Q” raises two very important yet controversial issues regarding the etiology of autism (see comment). I’ll address each factor separately, but with the understanding that even though we don’t have all the answers regarding the impact of environmental factors and vaccinations as possible causes of autism, much research has been done and continues to be done.
Environmental factors continue to be looked at by researchers in the field, with the most recent studies focusing on factors that may be present when the child is in utero. The first looked at prenatal exposure to certain antidepressants as well as certain viral illnesses. Each variable increased the risk of having a child with autism, especially when they occurred within the first three months of pregnancy. Other studies have looked at other environmental influences such as vitamin deficiencies, obstetric complications, environmental toxins and immune challenges. Each study has associated these environmental influences with an increase in autism, so these factors have been linked to the development of autism but have not been determined to be the sole causal factor.
Regarding vaccinations as a link to autism, there have been several reliable and valid studies, the first published in 1999 conducted in the UK by the Department of Health, and the second conducted by a panel of 15 experts from the Institute of Medicine. Each of these initial studies found that there was no connection between the MMR (Measles, Mumps and Rubella) vaccination and autism. Additionally, a paper published in 2004, which consisted of a comprehensive review by the Institute of Medicine also found no causal relationship between vaccines and autism. Even with these well designed studies, the idea that there is a link between vaccines and autism will surely persist even in the face of scientific evidence.
I’d also like to bring up the genetic factors that are most definitely part of the equation. The facts that boys are four times more likely to develop autism than girls, second children born to parents who already have a child with autism are more likely to develop autism, and the multiple twin studies that have been done indicate a fiercely strong link between genetics and autism.
The bottom line is, we don’t know what we don’t know. Our best educated guesses based on the research that has been conducted and published point to the fact that we do have to look more closely at possible environmental influences as a cause of autism, and how these factors may come together with the genetic component in the etiology of autism.
As a professional in the field, the one thing that is certain is that once early warning signs of autism are identified, a diagnosis and subsequent intervention is vital in the improvement of individuals with autism throughout their lifespan.