What Causes Autism?

Hip Inc Administrator
Nov 1
11 min read

By: Jonathan Alderson

Is there any ONE cause of autism? Does Tylenol cause autism?

NO! There is not a single cause for autism.

Yet there is so much controversy and mixed messaging to parents and caregivers today on this topic.

That’s why I’ve written this article to share the real facts.

I’m Jonathan Alderson, and I have been working with, supporting, and caring for autistic individuals and their families for over 30 years.

Keep reading to learn about the spectrum of autism and why that is important to understand that there is no ONE cause of autism, real scientific research examples, and facts that we DO know, as well as the implications of unscientific theories.

So.. why is there no single cause of autism?

The reason is that the autistic population is so diverse. There's such a huge range of what autism looks like.

Let's back up for a minute. Let's talk about autism and what autism is, so you can understand the causes.

What is Autism?

When we look at the behaviors that we measure as autism, it's a cluster of behaviors that fall within a couple of different categories;

Social Communication

Social communication is how an individual communicates socially, how they have a conversation, how they understand language, and how they perceive social situations around them. This may be different or unique in an autistic individual.

For example, I could be sitting talking with you, and as an autistic person, I may not be thinking about nodding my head to let you know I understand what you’re saying. Even though I might completely understand. However, there's lots of autistic individuals who DO nod their head and DO look in your eyes and DO signal in that way, but they might have a completely different social communication challenge.

In other words, the range is SO broad.

Repetitious and Ritualized Behaviors (Stimming)

Repetitious and ritualized behaviors, which you may know commonly as stimming, is a hallmark of autism.

I have worked with autistic children who would stack their toys all in a row as far as the eye could see, one beside each other, and then they’d scoop them up and redo it all over again. And when I watched closely, I noticed the toys were in the exact same sequence each time.

I've also worked with highly verbal autistic individuals whose repetitious ritualized behavior happens within their language. For example, a 13-year-old boy I worked with years ago would have the same conversation with you about Hawaii and going to the beach over and over again. I wouldn't notice at the beginning, but maybe 3 or 4 minutes in, I’d realize, hey, wait a minute. “Didn't you just ask that same question?”

I could list literally tens of thousands of different repetitive and ritualized behaviors.

These are just two of the categories of the cluster of behaviors that define autism, and you can already see such a vast diversity.

What autism looks like and how individuals experience autism is a range, which is why it is called the autism spectrum.

The Autism Spectrum

What used to be called Autism Disorder is now Autism Spectrum Disorder or ASD.

Scientists call this a heterogeneous population as opposed to a homogeneous population, meaning it's diverse - no two experiences are the same.

And modern research scientists today believe that there are many different ways you could get to the same cluster or similar cluster of behaviors that we call autism.

How is it possible that there could be many pathways to a similar kind of symptomology?

Well, let's take headaches as an example.

Headaches are a common symptom that people experience around the world, but there are many different ways that you could get a headache, right?

One way that I figured out when I was young is if you drink too much tequila, you can get a headache! You can also get a headache from not drinking enough water, i.e., dehydration. Or from a virus, i.e., if you have the flu or a cold. You can also get a headache from an injury!

So, one symptom yet many different pathways to get that symptom.

Now, autism is a range of different symptoms or behaviors that are clustered into different categories. AND much like the headache analogy, there are different pathways to these behaviors.

Let’s look at what a couple of those different pathways could be:

Genetic Causes of Autism

To date, the scientific community hasn't discovered a single “autism gene”.

It's actually a cluster of genes that can have snippets, deletions, or different kinds of configurations that can lead to things like some of the symptoms of autism.

For example, there are genes related to hyperactivity and genes related to anxiety, obsessive-compulsive disorder, and ADHD. And some of these symptoms coexist with autism.

For example, there's a higher incidence of anxiety disorder in the autistic population than you'd find in the neurotypical population. And so, there's likely genetics involved.

So is there a single autism gene? No.

But, when people ask me, is autism a genetic disorder? The answer is yes, it's related to genes, but no, there isn't a single autism gene that we know of yet.

But let's go even further into that, looking at the research of some of the leading geneticists in the world.

Research on Autism Genetics

Steven Sheer is a world leader of genetics at Sick Kids Hospital in Toronto, Canada, and has published a number of papers in which he explains that what we're looking at is two things: the first is epigenetics.

Epigenetics and Environmental Causes of Autism

Epigenetics means that yes, there are genes involved in a particular symptomology, but that the genes can be expressed depending on environmental factors.

Genetics = Gene

Epi = Phenomena around the gene

The phenomena around a gene can vary. For example, stress, diet, or sleep patterns can influence whether a gene is turned on or turned off - literally like a light switch.

This is a simplified explanation - but think about a friend you know who may be genetically predisposed to heart disease. That means they're carrying a gene or some genes that are related to heart disease but could potentially lower the risk by eating better or exercising more frequently.

So it’s genetic and environmental?

Well, it CAN be! Even when we talk about genetics, Steven Sheer will suggest that to date we can only account for a certain percentage of autism due to genetics and that there may be other factors.

So let's discuss a couple of the other factors:

Biological Causes of Autism

Let’s look at biological makeup, meaning there may be things that happen in our physical body that can produce certain symptoms.

Biologically, there is really interesting research done by a doctor named Derek Macfabe, who dives into a particular bacteria in the gut that exists in humans and an amino acid that this bacteria produces.

What he was able to show is that the amino acid can travel up from the gut, cross the blood-brain barrier, can trigger or lead to some autistic symptoms like repetitive ritualized behavior.

And when you're able to decrease that bacterial load in the gut, therefore decreasing the amino acid load on the brain, the repetitious ritualized behavior is decreased.

BUT that's only one study on repetitious ritualized behavior.

There's another biological study done by Dr. Mary Megson. She was a researcher looking at repetitive ritualized behavior in autism, but was looking specifically at hand flapping (a common repetitive behavior)

Dr. Megson’s research showed that some autistic individuals (not all autistic individuals) who flap their hands may do so because of a low amount of a certain kind of vitamin A, which is beta carotene.

Now, beta carotene is needed for the receptors in our eyes. In order for light to come in and to bind to the receptors, you need beta carotene. Her theory was that some autistic individuals don't have enough of this kind of vitamin for the eyes and therefore they're using hand flapping as a way to stimulate the peripheral vision that isn't working as well, or sometimes to create a boundary to say “This is where my right is… this is where my left is” visually so that they can navigate their environment.

Again, it was for a small population. But there are two examples of how you might come to repetitive ritualized behaviors. One is through an amino acid up in the brain, and the other is through a low nutrient supply.

And there may be many other reasons - that have nothing to do with biology - why an individual might line up objects. It could be wanting to find some sort of control in their environment, or it may simply be calming.

So, with all of this said, we can then fairly confidently conclude that there is no one cause of the cluster of symptoms that define autism. So what does Tylenol have to do with all of this?

Does Tylenol Cause Autism?

Recently, the president of the United States and his Secretary of Health, RFK, have claimed that Tylenol causes autism in pregnancy and warned mothers not to take it.

And I am not here to make a comment on that because I'm not a medical doctor or a researcher of Tylenol, or a politician.

I don't side with either party in the United States.

BUT, I can say this with confidence; there is no good, accepted, conclusive, scientific evidence that shows that Tylenol causes autism. You won’t find it. You won't find a published paper that will show that conclusively.

Now, there is some research that has been done on acetaminophen - the active medical ingredient in Tylenol - and how it might have an impact on the physical body.

One interesting note is that it does get involved in metabolism; how we digest and use acetaminophen does get involved in the methylation cycle in the body. And there is some research on the part of the human genome where methylation happens. It's called MTHFR.

So, there is a relationship there, but does that mean that acetaminophen causes autism symptoms? No, we don't have evidence of that. It is not conclusive.

The Implications of President Trump’s Statement on Tylenol and Autism

It is extremely dangerous to be telling moms who may need to take something like Tylenol or acetaminophen - if they have a fever that may cause harm to their fetus - that they shouldn’t.

Now, I'm not here to say “Yes, take Tylenol” or “No, don’t take Tyenol”, but as far as we know, Tylenol is safe to take in those situations under medical supervision.

I think what's missing in this discussion of what causes autism is the starting point that the autistic population is heterogeneous - like I mentioned at the beginning of this article, it's a huge range. Every individual is unique. Therefore, every individual has their own genetic makeup, their own challenges, strengths, weaknesses, interests, and motivations.

If we started at a point of recognizing that we have such a broad range of neurodiversity, then we could allow ourselves to then say maybe there are sub-populations. Some people may come by the autistic cluster of symptoms - what we call autism - through genetics or through epigenetics and the environment. Some may be through biological challenges.

There may be a whole number of ways that we get this wonderful diversity within the autism population.

Why We Shouldn’t Be Looking for the “One Cause of Autism”

The problem with such a high-powered person as the president of the United States coming out and saying that there's one cause of autism or a main cause is firstly, all the parents who stop taking Tylenol, who may need it really for the safety of themselves and their fetus.

Secondly, it pulls attention away from really important research that's happening in other areas of autism.

Many are also concerned about the apparent disregard for good science in the U.S. President’s statements.

When we talk about research and science, there are standards - a scientific approach and method. So, for example, you would typically want a control group and you’d want it to be randomized. And that's just a baseline where you would start with good research. Then there are standards of how to collect data, peer reviewing, and so forth.

It seems like the U.S. President and RFK are disregarding a lot of those conventions, and I think what becomes dangerous is when we start floating out ideas that aren't following the global standards of research.

Implications for Parents of Autistic Children

Parents, especially mothers, also feel guilty when they hear that something might have caused their child to have autism. They go back in their mind and think, "Oh, was it something I did?"

I remember having a conversation with a mom when I was working in England. We sat on a bench in her yard and when I asked her how she was feeling, she started to talk about the guilt that she'd been carrying for years.

Her child was 5 years old, but from a much younger age, she noticed he had different behaviors and wasn't developing in the way she had imagined. When her son got his autism diagnosis, she would lie in bed every night going through all of the things that she may have or not have done correctly in her mind during the pregnancy and while raising him.

This is an example of what parents and mothers in particular do. They look back over their pregnancy and say, "Was it the argument I had with somebody that maybe stressed my baby? Was it that glass of wine I had? Was it not getting enough sleep? Was it not eating, taking enough vitamins? And so on and so forth."

So, all of these different theories of what causes autism can lead to a lot of guilt.

The History of Theories

There have been many different theories in the past as to a sole cause of autism, all without conclusive research, and many blaming parents and mothers in particular.

Decades ago, back in the 1960s, a psychologist from Germany, Bruno Bettelheim, came to the United States and worked as a professor at the University of Chicago. He proposed the idea that the reason children are autistic is that their mothers didn't love them enough. It was called the refrigerator mother theory.

Can you imagine what that did for mothers? And the guilt?

Surprisingly, that theory was around for a while, but of course, it was eventually completely debunked, and Bettelheim lost his job.

It is a sad ending as he ended up committing suicide because there was so much social pressure and backlash on him.

But it shows just how careful we need to be about the kinds of theories and ideas we put out into the general public and the loving, caring parents who adore their children.

What to Remember If You’re a Parent

Even if one pathway can lead to some of the symptoms of autism that one individual has, it doesn't mean that your specific child came by autism through that path.

There may be many, many different ways that you come by the same cluster of symptoms.

And because each individual with autism is unique and multifaceted, any education, support, or therapy to help an autistic individual thrive should also be multifaceted.

So I want to encourage parents to really get to know and understand their unique child. There's no other child that's ever been born or ever will be born like your little one.

And so you want to really get to know and understand your unique child's unique profile. This is what we call precision autism care - looking at an individual and then creating a unique, individualized roadmap and plan for that individual to thrive and live their best life.

And that's exactly what my new online platform does: ThriveGuide. It generates a unique set of recommendations that's matched to unique profiles based on parent input.

By: Jonathan Alderson