From Disorder to Difference: How Our Understanding Has Changed
The way we understand neurodivergence today is very different from how it was understood even a few decades ago.
Autistic people have always existed.
People with ADHD have always existed.
People with dyslexia, dyspraxia, Tourette's and other neurological differences have always existed too.
What has changed is our language, our understanding, and, slowly, whose voices we listen to.
For much of history, neurodivergent people were understood almost entirely through the eyes of other people. Doctors and researchers observed behaviour from the outside and tried to explain why someone acted differently from what society expected.
Today, we are beginning to ask a different question.
Not simply:
"What does this person do differently?"
But:
"What is this person actually experiencing?"
That shift has changed almost everything.
Before We Had the Words
Long before terms such as autism or ADHD existed, people would still have experienced the traits we now associate with them.
The child who couldn't sit still.
The adult who became overwhelmed by noise.
The person who needed routine and predictability.
The student who could understand complex ideas but struggled to read.
The person who could focus intensely on something they loved but found everyday tasks almost impossible to begin.
Without the understanding we have today, these differences were often interpreted as problems with behaviour, intelligence, parenting, or character.
People weren't necessarily struggling because neurodivergence was new.
We simply didn't yet have the language to understand what we were seeing.
The Early Medical View
The history of autism and ADHD shows just how dramatically our understanding can change.
In the early 20th century, behaviours we might now recognise as ADHD were described using deeply judgemental ideas about a person's "moral control".
The word autism was first used in 1911, but it was originally associated with schizophrenia rather than recognised as a distinct form of neurodevelopmental difference.
By the 1940s, autism began to be described as a separate condition. But these early descriptions were based on a relatively narrow group of people, often children whose differences were particularly visible to those around them.
This shaped our understanding for decades.
If someone didn't look like the limited picture professionals had been taught to recognise, they could easily be missed.
When Parents Were Blamed
Some of the historical explanations for neurodivergence were not just inaccurate - they were incredibly harmful.
For a time, theories suggested that autism could be caused by emotionally distant parenting, particularly by mothers.
We now know this was wrong.
But imagine the impact of being a parent who was already trying to understand and support their child, only to be told that they had caused their child's differences.
These ideas influenced families, professionals and society for years.
It is an important reminder that what is considered accepted knowledge can change, and that we should always be willing to listen to the people whose lives are actually being discussed.
Autism Becomes Its Own Diagnosis
It wasn't until 1980 that autism was formally separated from childhood schizophrenia in the DSM, one of the diagnostic manuals widely used in psychiatry.
Even then, the criteria remained narrow.
The people most likely to be recognised were often those whose traits were visible to others.
People who could speak fluently, maintain relationships, work, make eye contact, or hide their difficulties could easily fall outside the picture.
This contributed to generations of people growing up without understanding why life seemed to require so much more effort for them than it appeared to require for everyone else.
The Spectrum Begins to Widen
During the 1980s and 1990s, understanding began to expand.
The idea of autism as a spectrum became more widely recognised, and Asperger's Syndrome was introduced into diagnostic systems.
Whatever we now think about the language and history surrounding that diagnosis, its introduction meant that many people whose autistic traits had previously gone unrecognised finally began to be seen.
In 2013, separate autism diagnoses, including Asperger's Disorder, were brought together under the broader diagnosis of Autism Spectrum Disorder in the DSM-5.
For some, this helped recognise that autism is not one narrow presentation.
For others who strongly identified with the Asperger's label, the change brought a sense of identity loss.
Progress is rarely simple.
ADHD Changed Too
The story of ADHD followed a similar path.
For decades, the focus was largely on children who were visibly hyperactive or disruptive.
The stereotypical picture became the young boy who couldn't sit still in a classroom.
But what about the child staring out of the window?
What about the girl quietly struggling to follow a lesson, because she either cannot focus on anything, or is focused on far too many things all at once?
What about the adult who could manage a complex crisis but couldn't remember to pay a routine bill?
As understanding developed, attention difficulties without obvious hyperactivity became more widely recognised.
Later diagnostic criteria acknowledged different presentations of ADHD and, eventually, gave greater recognition to the fact that ADHD does not simply disappear when someone turns 18.
That change has helped many adults finally find an explanation for experiences they have carried throughout their lives.
Why So Many People Were Missed
Our understanding of neurodivergence was historically built largely around what professionals could observe from the outside.
But internal experiences are much harder to see.
You cannot always see:
Sensory overload.
Executive dysfunction.
The effort required to maintain eye contact.
The hours spent rehearsing conversations.
The exhaustion after appearing "fine" all day.
The racing thoughts behind a quiet face.
The panic caused by an unexpected change.
When diagnostic systems focus primarily on visible behaviour, people who learn to hide their differences can disappear from view.
This is one reason so many adults, particularly women and people whose presentation does not match traditional stereotypes, are only now discovering their neurodivergence.
The Cost of Being Missed
For many late-identified neurodivergent adults, diagnosis or self-understanding brings relief.
But it can also bring grief.
There can be a lifetime of questions to revisit.
What if someone had understood?
What if I'd had the right support at school?
What if I'd known I wasn't lazy?
What if I'd been allowed to rest instead of constantly pushing through?
Many people spent decades being treated only for anxiety, depression, burnout or other mental health difficulties without anyone asking whether unsupported neurodivergence might also be part of the picture.
Others learned to mask, consciously or unconsciously hiding their natural responses in order to fit the expectations around them.
From the outside, they may have looked like they were coping.
Inside, the cost could be enormous.
When Two Conditions Couldn't Exist Together
Our changing understanding can also be seen in the relationship between autism and ADHD.
Today, many people identify as both autistic and ADHD, sometimes using the informal term AuDHD.
Yet for years, diagnostic systems did not allow someone to be diagnosed with both.
The person didn't change when the diagnostic rules changed.
The rules simply became better able to describe a reality that had been there all along.
For many people, this is the history of neurodivergence in a nutshell.
People did not suddenly become neurodivergent.
Our understanding caught up.
The Neurodiversity Movement
Perhaps one of the biggest changes has happened outside the medical system.
From the 1990s onwards, autistic self-advocates increasingly challenged the idea that the goal should always be to make neurodivergent people appear less neurodivergent.
The neurodiversity movement helped introduce a different way of thinking.
Instead of asking:
"How do we make this person more normal?"
We can ask:
"What barriers are making life harder for this person?"
That does not mean pretending neurodivergence never comes with difficulties.
Some neurodivergent people have substantial support needs. Some experience disabling challenges that affect every part of daily life.
The neurodiversity approach does not require us to ignore those realities.
It asks us to recognise that support and acceptance can exist at the same time.
We can help someone communicate without insisting they communicate like us.
We can support executive functioning without calling someone lazy.
We can reduce sensory distress instead of teaching someone to silently tolerate it.
We can support people with the things they find difficult without trying to erase the things that make them who they are.
Nothing About Us Without Us
For much of the history of neurodivergence, professionals spoke about neurodivergent people.
Increasingly, neurodivergent people are speaking for themselves.
Lived experience is becoming part of research, policy, education and public conversations.
That matters.
A clinician can observe that someone avoids eye contact.
An autistic person can explain that making eye contact uses so much concentration that they can no longer process what is being said.
A teacher can observe that a child won't sit still.
Someone with ADHD can explain that movement may actually help them concentrate.
What something looks like from the outside and what it feels like from the inside can be completely different.
We need both perspectives.
Social Media Changed the Conversation
The rise of online neurodivergent communities has transformed access to information and lived experience.
For the first time, many adults encountered other people describing experiences they had never been able to put into words.
They heard about masking.
Sensory overwhelm.
Executive dysfunction.
Autistic burnout.
Time blindness.
Rejection sensitivity.
And sometimes, for the first time, they thought:
"Wait. Other people experience this too?"
Social media is not a diagnostic assessment, and information online should always be approached thoughtfully.
But it has given neurodivergent people something previous generations often didn't have:
The ability to find one another.
And that has helped change the conversation.
We Are Still Learning
Our understanding of neurodivergence will continue to change.
The language we use today may not be the language people use in fifty years.
Research will develop.
Diagnostic criteria will change.
Neurodivergent people will continue telling us things about their experiences that previous models failed to capture.
That isn't a failure of science.
Changing our understanding when we learn more is exactly what progress should look like.
But history should also teach us some humility.
Many people who were once considered badly behaved, difficult, lazy, over-sensitive or incapable may simply have been living in a world that did not understand their brains.
There are undoubtedly people experiencing that same misunderstanding today.
A Final Word
The history of neurodivergence is not simply a history of diagnoses.
It is the history of real people trying to understand themselves in a world that often misunderstood them first.
We have moved from moral judgement, blame and narrow definitions towards a much broader understanding of neurological difference.
There is still a long way to go.
Perhaps the biggest change is that the question is slowly shifting.
From:
"What is wrong with you?"
To:
"Why are you struggling?"
And ultimately:
"What would help?"
That is the future we want to help build.
A world where neurodivergent people do not have to wait for society's understanding to catch up before they are listened to, supported and valued.