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Is autism on the rise? And why?

Boy playing at a table
Credit: iStock.com/Feverpitched

Autism. It’s a condition we hear a lot about, but how much do we really know about it?

Fifty years ago it was rare to hear about someone having autism. These days, it seems much more prevalent in our children, or our friends’ children. Everyone knows someone who’s on the spectrum. 

Have autism numbers risen, or are we just over-diagnosing our children to explain away behaviour we don’t understand? 

With a sharp increase in autism diagnosis it might seem that way, but experts say there are valid reasons the increases- some biological and some related to strides in modern medicine. 

Autism numbers, according to the Australian Bureau of Statistics, have increased dramatically within the past ten years. 

La Trobe University Olga Tennison Autism Research Centre director Professor Cheryl Dissanayake says the reasons autism diagnosis have risen are complex and varied. 

“In the 1980s we used to cite 3-4 in 10,000 births would result in a diagnosis of autism.  Now we say 1-2 per cent of the population will meet the criteria for an Autism Spectrum Disorder,” Professor Dissanayake says.

“There is not just one reason for the increase and I certainly wouldn’t say there is an autism epidemic, these numbers have always existed but we just weren’t picking them up,” she says.

Why has there been an increase? 

Professor Dissanayake argues the reasons behind the increase in autism are complex and varied and the result of biological issues, modern medicine and more sophisticated diagnostic tools.

While autism was first identified in 1943, it only made it into the Diagnostic and Statistical Manual (DSM) in 1980. 

There is not just one reason for the increase and I certainly wouldn’t say there is an autism epidemic, these numbers have always existed but we just weren’t picking them up.
Professor Cheryl Dissanayake

“The first reason I think we are seeing an increase in autism is that what we used to call autism in the past has changed. We were only really picking up the more severe kids and we thought that autism was just one condition,” she says.

“We now know that autism is a lot of things - a body of conditions and we recognise as a spectrum”.

“And we weren’t picking up either end of the spectrum, so kids with severe intellectual disability didn’t used to get picked up and at the other end, kids who were very verbal and cognitively able but still quirky, also weren’t picked up.”

“So autism is a much broader spectrum than we realised and now we pick up both ends, so of course the numbers have increased.”

In other words, our understanding of autism has improved over time.

Medical advancements were another reason for the rise in autism diagnosis, according to Professor Dissanayake.

With better survival rates for premature babies, there were more children born at risk of autism, she says.

“Anything that affects the developing brain is a risk for autism and being born premature is a risk factor.”

The increasing age of fathers has also been repeatedly identified as another factor leading to an increase in autism diagnosis, says Professor Dissanayake.   

“We used to think maternal age was linked to autism but it is much more likely that paternal age is a greater risk factor.”

How is autism diagnosed? 

Diagnosing a child with autism can be tricky, because there is no blood test or scan that can help. Instead it is based on criteria related to observing the child and learning about their developmental history. 

Professor Dissanayake says it is parents and carers who have the best insights into whether or not a child needs to be assessed.

“Parents should always act on their instinct and if they think something isn’t right then they should get their child assessed,” she says. 

There were two core areas health professionals looked at when making an autism diagnosis. They are:

  • Social communication and a child’s ability to communicate in a reciprocal way with other people.
  • Restricted or repetitive behaviour or interests like having to do the same things in the same way over and over again, or getting upset when things aren’t done the same way every time. 

Professor Dissanayake says autism occurs across a range of cognitive abilities. 

A child health nurse or GP could be the first port of call for support, but ultimately a paediatrician should organise an assessment of the child.

“I can’t stress enough that a parent shouldn’t wait and see if their child will improve in certain areas, you know your child best and if you have concerns go and see your GP and get a referral to a paediatrician. If the GP doesn’t think you need one and you still have concerns then go elsewhere,” she says.

“It is really important that the child accesses early intervention and that parents and educators are supporting that child in similar ways across all of their activities,” she says.

I can’t stress enough that a parent shouldn’t wait and see if their child will improve in certain areas, you know your child best and if you have concerns go and see your GP and get a referral to a paediatrician. If the GP doesn’t think you need one and you still have concerns then go elsewhere.
Professor Cheryl Dissanayake

Early intervention is the key to supporting children with autism, says Professor Dissanayake. 

“A lot of the work we have done (at the Olga Tennison Autism Research Centre at La Trobe University) over the past few years is around bringing the age of diagnosis down to infancy and toddlerhood,” she says.

“The earlier the diagnosis the earlier the access to services and the better the outcomes for the child.”

“We have found that children diagnosed by the age of two are doing much better than those diagnosed later. The majority are in mainstream schools and have no signs of an intellectual disability.”

The Olga Tennison Autism Research Centre was currently working on a national push to get children with autism diagnosed earlier. 

“Of children under age seven in Australia, the age of diagnosis is typically 49 months (4 years old), which is two years later than it should be. Ideally, we would like to see 100 per cent diagnosis by three years, and 70 per cent diagnosis by two.”

Is your child at risk of autism? 

The Olga Tennison Autism Research Centre has recently launched an autism detection app for parents to check their children for early signs of autism.

The free ASDetect app is aimed at children from 11 to 30 months and contains a list of predictive behaviours based on specific ages.

Parents are asked a series of questions, shown videos and sent an assessment which provides instructions on next steps. 

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