The Autism Debate: What Causes It?
Earlier this year, Sesame Street added a new character to its popular and enduring television program.
Julia, an adorable four-year-old, with a shy smile and red hair, looks like a typical Muppet. She’s upbeat, loves to pick flowers, paint, and sing. However, sometimes Julia will repeat certain words or phrases and she may not answer questions on the first try. The occasional loud noise can also cause her to become upset.
Julia’s breakthrough character has Autism Spectrum Disorder (ASD) or autism for short.
And he’s not alone. One in 68 children is considered to be on the autism spectrum, living with varying degrees of the condition.
Autism is a developmental disability. It occurs across all racial, ethnic, and socioeconomic groups around the world. While the underlying causes of ASD are still largely unknown, most researchers believe there are genetic components and that it can run in families. Other factors might include metabolic, neurological, bio-chemical, and environmental factors.
Typically, autism is characterized by difficulties in social interaction, communication, and certain behaviors, which can vary widely but sometimes include the following:
- Repetitive behavior
- Adherence to routines
- Difficulties relating and empathizing with others
- Sensatory sensitivities
- Highly focused interests
Even though researchers have been studying ASD for many years, its origins and pathology largely remain a mystery, and there is no definitive test or scan that can identify the condition. Instead, diagnosis is made by observation of infant, child, or even adult behavior.
“Scientists spent decades looking for a specific gene, or a specific part of the brain, that could be causing the symptoms of autism,” wrote journalist Alexandra Ossola, in a recent report published on CNBC.
“But that work hasn’t turned up any one specific answer. Instead, researchers have had to change their questions,” noted Ossola. “They now suspect that autism, like other complex diseases such as cancer or obesity, comes about by the interaction of many different genes and environmental factors. Researchers estimate that there may be hundreds of genes that could make someone more likely to develop autism; but merely having any one of those genes doesn’t determine whether or not the disorder develops, or how severe it is if it does.”
Even though the root cause has been elusive, scientific research has revealed many aspects of the condition.
For example, ASD is now viewed on a broad spectrum and unique in every person who has it.
This uniqueness was aptly described by Dr. Steven Shore, who has written several books about autism and also lives with the disorder himself – “If you’ve met one person with autism, you’ve met one person with autism.”
The Centers for Disease Control and Prevention (CDC) has identified a number of ASD risk factors ranging from environmental to biologic to genetic. Here is a partial list:
- Family history
- Premature birth
- Viral or bacterial infections in mothers during pregnancy
- Obesity in mother during pregnancy
- Prenatal or early childhood exposure to toxic chemicals and some air pollution
- Older birth parents, particularly fathers
- Genetic or chromosomal conditions, including tuberous sclerosis and fragile X syndrome
Missing from the risk factors are childhood vaccines, long a source of contention.
In 1998, childhood vaccines, specifically the measles-mumps-rubella (MMR) vaccine, were tied to ASD in a study led by Dr. Andrew Wakefield, a gastroenterologist and native of Britain.
Wakefield examined a dozen children living with autism, honing in on chronic enterocolitis, inflammatory bowel disease and regressive developmental disorder. In his results of this small study, Wakefield suggested a link existed between the MMR vaccine – which is usually administered between 12 and 15 months of age – and autism.
This now debunked theory was published in the medical periodical The Lancet.
As lead author, Wakefield wrote: “In eight children, the onset of behavior problems has been linked, either by the parents or by the child’s physician, with measles, mumps and rubella vaccination.”
The study garnered media attention and headlines around the world. However, in the autism research community it was met with great skepticism among experts. And, almost immediately 10 of the paper’s co-authors backed away from any MMR link by issuing a retraction of the interpretation of the data.
A later, comprehensive investigation concluded Wakefield had both misrepresented and altered the medical histories of the study participates. He had also failed to disclose that his study was receiving funding from attorneys who had brought suits against vaccine-producing companies. By 2010, Wakefield’s study had been fully retracted, and a year later he was stripped of his medical license.
However, in the autism family community, Wakefield’s conclusions had spread like wildfire.
Parents desperately looking for a reason for their child’s autism were drawn to his theory. Out of this environment, and perhaps fueled by a burgeoning internet, a massive anti-vaccine movement took root. Vaccine rates plummeted and have remained lower. Unprotected against contagious diseases, measles and mumps outbreaks have erupted and left many children vulnerable. Even today, the fear of some sort of a connection between vaccines and autism persists among many parents.
This distress is reflected in two 2014 opinion surveys. The first, conducted by the National Consumers League, revealed one-third of American parents mistakenly link vaccines to autism, while another survey by The Associated Press indicated only 53 percent of Americans were confident that vaccines are safe and effective.
Autism researchers like Mayada Elsabbagh, professor of psychiatry at McGill University, hope Wakefield’s study and the ensuing controversy will soon fade into the past. “Regarding vaccines, the case has been closed for many years as far as the evidence is concerned,” said Elsabbagh.
The Centers for Disease Control and Prevention (CDC) writes unequivocally on its website, “Vaccines Do Not Cause Autism.”
Alycia Halladay, the chief science officer at the Autism Science Foundation, agrees and called the discussion about vaccines and autism a “distraction” because money spent looking into it wasn’t dedicated to more pressing research questions.
Private and government research has focused many studies on this subject. One study was a comprehensive, evidence-based, meta-analysis of 1.2 million children. The results were revealed on the National Institutes of Health website: “Findings of this meta-analysis suggest that vaccinations are not associated with the development of autism or autism spectrum disorder. Furthermore, the components of the vaccines (thimerosal or mercury) or multiple vaccines (MMR) are not associated with the development of autism or autism spectrum disorder.”
Today, autism researchers are moving ahead, looking at new avenues of research and placing a greater emphasis on helping improve the lives of those living with the disorder. (Link to article 5)