Autism in adults: a late diagnosis and how much it explains

The party was lovely. Everyone laughed, the food was good, nobody said anything wrong. And yet she has been sitting in the car park for twenty minutes, engine off, no music, unable to drive away. She is not sad. She is not angry. She is simply empty, as if she had spent the whole evening carrying something heavy that nobody else could see.

At home she opens her phone and, somewhere in the middle of the night, reads an article about autism in adults. By the third paragraph her hand is shaking. “It’s as if someone were reading my diary,” she thinks. She is forty-one.

Stories like this come up more often today than they used to. More and more people learn about autism in adults only in midlife — sometimes along their own path, sometimes when their child is diagnosed. This piece is about what autism is, why we take so long to recognise it in adults, and how much a late diagnosis can explain about a life that, until then, had been written in another language.

What autism is — and what it isn’t

Autism is a difference in the development of the nervous system that affects how a person perceives the world, how they communicate and how they respond to change. It is present from childhood; it does not develop in adulthood. In the International Classification of Diseases, ICD-11, it is called autism spectrum disorder, while among autistic people and in parts of the profession the broader term neurodivergence is used more and more — a term that emphasises a different way of functioning, not a broken version of the “usual” one.

The word spectrum is often misunderstood as a scale from “mild” to “severe”. It is more accurate to picture a mixing desk with several sliders: one person has very pronounced sensory sensitivity and hardly any difficulty with conversation, another the reverse. Two autistic people can be more different from each other than either of them is from someone who is not autistic.

Language is worth pausing on, too. A study published in 2016 by Lorcan Kenny and colleagues showed that autistic adults, parents and professionals have different preferences about terminology: many autistic adults prefer to say “I am autistic”, because they experience autism not as something they carry around, but as part of who they are. So in this piece I write “autistic person” or “person on the spectrum”. If you prefer another term, your choice is the one that counts.

Why so many adults go unrecognised

In 2011, Traolach Brugha and colleagues published the first study to look for autism among adults in the general population of England — not in clinics, but door to door. They estimated that around one per cent of adults are autistic, and found that most of them had no diagnosis. These people went to work, had families, paid their bills — and nobody knew they were on the spectrum. Often not even they did.

There are several reasons. Older diagnostic criteria were shaped mainly by experience with boys whose traits were very visible. Someone who was quiet, well-behaved and had “only” a few friends did not attract attention. Many learned early on to imitate others, rehearse conversations in advance and hide whatever might be noticed. This is called masking or camouflaging, and because it is more common in women and often exhausting, it has its own piece, Autism in women and the masking that wears you out.

It also often happens that a person first receives another name for their distress: anxiety, depression, burnout, a “difficult personality”. These difficulties can be entirely real — autistic people are, if anything, more vulnerable to them. But if nobody sees what lies underneath, only the tip of the iceberg gets treated.

How it can show in an adult’s everyday life

You cannot recognise autism by a single sign, and no online list is a test. But I can describe some experiences that autistic adults often talk about — not so that someone recognises themselves and draws conclusions, but to make it easier to understand what we are talking about.

• Conversation as work. Chatting about the weather is not relaxing but tiring, because it is unclear what it is for. Phone calls get put off, because there is no face to see and no time to think.
• Senses without a filter. The hum of the fridge, the label in a T-shirt, strong perfume in a lift — things others barely notice can take up all of your attention.
• Body signals that arrive late. Hunger, thirst or tiredness are sometimes noticed only when they are already very strong. This ability to perceive the inside of the body is called interoception.
• A need for predictability. The same breakfast, the same route to work, a plan for the weekend made in advance. This is not stubbornness, but a way of saving energy for the things that cannot be predicted.
• Deep interests. A subject that absorbs a person for hours, weeks or years — and brings a calm and a joy they do not find anywhere else.
• Directness. Words mean what they mean. Hints, irony and “you know what I mean” can be confusing.

Importantly, everyone knows some of this, at least sometimes. With autism, the difference is that it is constant, that it has been present since childhood, and that together it shapes a whole way of being in the world.

A misunderstanding has two sides

For a long time it was assumed that autistic people struggle to understand others and that misunderstanding is their “fault”. In 2012 the autistic researcher Damian Milton proposed a different view, which he called the double empathy problem. When two people who perceive the world very differently meet, both find it hard to understand each other. Non-autistic people read autistic people just as poorly — it is simply that their way is the majority one, and so it counts as the norm.

Experiments support this idea too. In 2020, Catherine Crompton and colleagues showed that information passes between autistic people about as successfully as between non-autistic people, but breaks down more often when an autistic and a non-autistic person talk to each other. So the problem is not in one head, but in the space between two.

For self-image, this is a big deal. Someone who has heard all their life that they are “no good with people” may, for the first time, think: perhaps it is not that I can’t, but that I speak a different language — and that with some people I share it very well.

A late diagnosis: how much it explains

When an adult learns that they are autistic, something often begins that could be called a rereading of one’s own life. Friendships that somehow always slipped away at secondary school. Jobs where they were excellent at the work and exhausted by the coffee breaks. Years of thinking they were oversensitive, demanding or “weird”. Suddenly all of this is seen in a different light.

In 2009, Christine Punshon and colleagues studied how adults respond to a diagnosis received late. They titled their article with the phrase “not guilty verdict”: for many participants the diagnosis meant that they were not to blame for everything they had been reproached for over the years. But alongside relief, many also felt sadness and anger: why had nobody noticed earlier?

This sadness is part of the process, not a sign that something is wrong with the diagnosis. You grieve for your younger self, who needed understanding, and for the years that could have been easier. In the knowledge base I write more broadly about how grief unfolds — including for losses that are not a death.

A conversation like this might go something like this (composite, not a real person):

“I don’t know if I’m a different person now.”
“What has changed?”
“Nothing. And everything. I’m still the one who always left the party first. Only now I know why.”
“What is it like to know?”
“Easier. And sad. For so many years I tried to be someone I’m not.”
“What would you like to do with what you now know?”
“Maybe, for the first time, leave without apologising.”

Who makes the diagnosis and how to prepare

An autism diagnosis in adults is made by a psychiatrist or a clinical psychologist. A psychotherapist does not make it — and neither do I. Who has which role is explained in Who may diagnose, who may prescribe, and who leads the process.

For adults, the process usually includes detailed interviews, questionnaires and, where possible, information about childhood — from parents, siblings or old school reports. Because autism is present from childhood, this part matters, but with adults it cannot always be gathered in full. To prepare, you can use the tool preparing for a visit to the psychiatrist: write down examples from everyday life, not just general impressions.

Autism often overlaps with ADHD, and someone who has one may also have the other — this overlap is the subject of ADHD and autism together: when novelty and routine pull in two directions. A diagnosis should remain what it is: a map that helps you understand, not a name that sums you up. More on this in A diagnosis is a map, not a name for you: what the ICD says and what it does not.

Autistic burnout

Many autistic adults reach a diagnosis precisely after a period when everything gave way. In 2020, Dora Raymaker and colleagues, working together with autistic co-researchers, described a phenomenon autistic people have long known: autistic burnout. It is long-lasting exhaustion in which abilities that previously worked also decline — speech, organisation, tolerance of stimuli. It develops after years in which the demands of the environment outstripped a person’s resources and masking used up whatever was left.

Autistic burnout is not the same as work burnout, although the two can overlap. A week’s holiday is not enough, because it is not tied only to work but to everyday life in an environment that has not been adapted. If you recognise the general signs of exhaustion, you may also find Burnout is not laziness: signs your nervous system is asking for a break helpful.

Recovery usually does not mean “more effort”, but less: less masking, fewer stimuli, more time in surroundings where you do not have to translate anything. For many people, the diagnosis is the first permission to take that time at all.

Exercise: an energy map for one week

This exercise is not a test and will not tell you whether you are autistic. But it helps you notice what drains you and what fills you up — whether you have a diagnosis, are seeking one or do not need one. In the knowledge base you will also find the template energy map through the day.

1. For one week, write down three things each evening that took the most out of you. Be precise: not “work”, but “a meeting where everyone talked at once”.
2. Also write down three things that filled you up. Perhaps a walk along the same route, an hour with your favourite subject, silence in the car.
3. At the end of the week, mark each item with a letter: S (sounds, lights, smells, touch), P (people, conversations), C (the unexpected, changes) or other.
4. Look at which letter keeps coming up. Don’t judge, just notice. You may find that it is not people who tire you, but the noise of the places where you meet them.
5. Choose one small adjustment for the following week: headphones on the way, five minutes of quiet after a meeting, a plan for Saturday written down on Friday. Watch whether it changes anything.

Your notes can also be valuable if you decide to seek a diagnostic assessment — concrete examples say more than a feeling that “everything tires you”.

Where this explanation does not apply

Not every kind of social tiredness is autism. Similar experiences can come with social anxiety, the after-effects of trauma, depression, ADHD or simply introversion. Social media is full of clips in which almost everyone recognises themselves — which is exactly why they are not a diagnostic tool. If you recognise yourself in a description, that is a good reason to talk to a professional, not an answer in itself.

A diagnosis does not explain everything. An autistic person also has their own family history, losses and wounds that have nothing to do with autism. If we put everything down to neurotype, we can overlook what needs attention in its own right.

Distress is not “just part of autism”. Depression and anxiety in autistic people are not something to be accepted as inevitable. They can be treated, with the right adjustments. A 2014 study by Sarah Cassidy and colleagues showed that suicidal thoughts are very common among adults diagnosed late. If you are having thoughts that it would be better if you were not here, do not wait: in Slovenia, call the crisis line Klic v duševni stiski on 01 520 99 00 (every day from 7 pm to 7 am) or the Samaritans helpline (Zaupni telefon Samarijan) on 116 123 (24 hours a day), and in an emergency 112.

Self-identification is nothing to be ashamed of. At the same time, a formal assessment can open access to adjustments and rule out other explanations. What is right for you is your decision — ideally made together with someone who knows you.

Relationships after a diagnosis and what therapy can offer

A diagnosis changes not only how you see yourself, but also your relationships. A partner may suddenly understand why you needed silence after a party and stop taking it personally. But the opposite can happen too: old resentments in the couple can resurface, now with a different name. Sometimes, when parents find out, guilt is stirred up — or one of them recognises themselves in the description as well. In relational family therapy, in which I am training, this is exactly what we look at: how an individual’s new explanation is written into the family system.

Therapy with autism is not meant to make you less autistic. It is meant to make it easier to live as you: to work through the grief the diagnosis brought, to explore where masking still uses up too much energy, and to find words for what you need in relationships. It is important to tell your therapist what helps you in conversation — for example, whether it is easier for you when questions are put more directly. Do I need a diagnosis to come to therapy? answers a question many people ask themselves before taking the first step.

Sessions take place in person in Ljubljana, and I also work in English. If you would like to look at how your story has intertwined with those of your family — and perhaps notice, in earlier generations, similar people whom nobody ever named — a longer session, A Look into the Past, with a genogram, is a good fit. As a therapist in training under supervision, I regularly bring my work to my supervisor.

What to remember

• Autism is a difference in how the nervous system works, present from childhood — it does not develop in adulthood, it is just often recognised late.
• The spectrum is not a scale from mild to severe, but a combination of different traits that is different for everyone.
• Misunderstanding between autistic and non-autistic people has two sides — the double empathy problem.
• A late diagnosis can bring relief and grief at the same time; both are understandable.
• The diagnosis is made by a psychiatrist or a clinical psychologist; therapy helps you live as yourself, not less autistically.