24 Jan, 2018

Autism

Public opinion vs latest research findings

Autism is complicated. How does public opinion stack up with the latest research?

We asked more than 200 people a list of common questions about autism. Do vaccines play a role in autism? What is the reason for the uptick in diagnoses of autism in the last decade? Are genes involved? Is it triggered by something in the environment?

This blog post looks at the answers we gathered from our survey and explores what is known from research for each of these questions. Before we begin, it is important to note that the causes of autism and the diversity of characteristics placed under this very broad category are far from being understood. These answers are not exhaustive and we still have a lot to learn from studying autism but they draw on the current scientific knowledge we have about it.

Does autism have anything to do with IQ?

Although many of our respondents thought that autism was linked to higher IQ, in fact autism can occur at any point on the IQ scale. That means you can have autism plus learning difficulties (below average IQ) or autism and average IQ, or even autism and above average IQ. If autism occurs with average or above average IQ it is called Asperger Syndrome, provided the person also developed language at the typical age (single words by 2 years of age). For medical professionals, the hallmarks of autism are actually just impairments in social interaction and communication, and unusually repetitive behaviours or unusually narrow interests, irrespective of the person’s IQ. Other common features of autism include sensory hyper-sensitivity, and a difficulty in adjusting to unexpected change.

Recent research in genetics may shed some light on why autism manifests differently across the autism spectrum, but more on that later!

Do vaccines cause autism?

Hearteningly, 80% of our respondents said that autism was not caused by vaccines, 18% were unsure, and just 2% thought there was strong evidence. Much larger studies have found between 6% and 10% of Americans believe vaccines cause autism.

This common myth is based in large part on a scientific study which was published in 1997 which claimed autism was caused by the MMR (measles, mumps and rubella) vaccine.

this study was eventually retracted by all of the lead author’s coauthors after it was revealed that the lead author had not disclosed his conflict of interest (some of the children’s families were seen as part of legal cases for example), that he had not adhered to his ethically approved protocol (some of the control group were recruited at a children’s birthday party for example), and because after a decade or more of research, it is clear that autism is not caused by vaccines. For example, subsequent large scale studies in countries where the MMR vaccine was only introduced to one part of the population found that autism rates did not differ among the vaccinated and non-vaccinated parts of the population. Nonetheless, the damage was done and the myth has persisted for decades.

Why are diagnoses of autism increasing?

The rate of autism diagnosis is undoubtedly increasing. Back in the 1970s scientists believed autism was rare, occurring in only 4 in 10,000 children. Latest studies suggest autism is common, occurring in about 1% of children. This increase is almost certainly due to greater awareness of the condition leading to previously unidentified individuals with autism being diagnosed. An overwhelming majority (95%) of our survey participants agreed with this. Also, 67% percent thought that changes in the criteria for diagnosis have contributed. This has been shown to be the case for a number of different countries and health systems.

Identified prevalence of Autism Spectrum Disorder

ADDM Network 2000 - 2012
Combing data from all sites

YearBirth yearPrevalence per 1000 children (range)This is about 1 in X children
200019926.7 (4.5 - 9.9)1 in 150
200219946.6 (3.3 - 10.6)1 in 150
200419968.0 (4.6 - 9.8)1 in 125
200619989.0 (4.2 - 12.1)1 in 110
2008200011.3 (4.8 - 21.2)1 in 88
2010200214.7 (5.7 - 21.9)1 in 68
2012200414.6 (8.2 - 24.6)1 in 68

Credits CDC

Where does genetics come in?

Just under half (48%) of respondents agreed that genetics had a role to play in autism. There has been decades of research on this topic, as far back as 1974 (on a set of 21 British twins.) Over the past four decades, studies suggest that 50–90% of the cause of autism is down to genetics. This is not to say that 50–90% of autism cases are caused by genetics alone — most cases will be caused by a combination of genetic and non-genetic factors. In other words, it is difficult to say for any one case of autism what the cause is, but we can learn something about the causes of autism across the whole population. Less than 1% of cases of autism are associated with a rare genetic mutation, so the genetic causes of autism are now thought to also include common variations in genes we all carry, occurring in particular combinations in those who go on to develop autism. The genes that have been identified are those that influence brain development, both brain structure and function.

Towards a 'cure'?

Many respondents to our survey were ‘uncomfortable’ with the idea of a ‘cure’ for autism. For many, in the absence of severe intellectual disability, it is not even clear that autism is a ‘disease’ that should be cured, rather than a different way of thinking. Nowadays the ‘neurodiversity’ view is that autism is both a disability (in social situations) and a difference (in processing information), and that we should of course be supporting the person with their disability whilst accepting, respecting and valuing their different way of thinking, which can sometimes lead to talent.

Lingering questions

It has long been known that autism is more common in boys than girls. This may be due to differences in how the diagnosis is made, or to exposure to sex linked hormones during fetal development, or to genetic differences, or to a mix of these factors. This is an area of very active research.

Finally, a big thanks to everyone who participated in this survey! If there are other questions, or ideas for what we can explore further please feel free to contact us!

Photo credit: Nick Youngson, Alpha stock images - Unsplash
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