The hidden cost of going undiagnosed with ADHD or autism as an adult

Many adults spend years masking their struggles, believing there’s something wrong with them. Campaigner Ellie Middleton explains why recognition, support and acceptance matter

But beneath the arguments about labels lies a more human question: do we really need to fully understand someone’s experience in order to treat them with compassion?

My teens have a ‘fun’ game at the moment. If one wants to annoy the other, they will tell them to “You are now breathing manually,” “You can feel your toes,” or “You are in manual blinking mode.” Cue the howls of “Stop it!” as all other thoughts swiftly depart their heads and the only thing they can think about is how to keep the oxygen flowing or why they really can suddenly feel their toes.

That’s a little bit like having autism or ADHD. But instead of occasionally being “made” to think about breathing, some people have to constantly monitor themselves. Watch their tone in conversations. Rehearse interactions before they happen. Try to maintain eye contact for the correct amount of time. Force themselves to sit still in meetings when every part of their body wants to move. Smile when they are overwhelmed. Pretend they are coping when their brain feels unbearably loud.

If you’re neurotypical you might have experienced this occasionally, perhaps in a job interview, or meeting the prospective in-laws.

But for many neurodivergent people, this is not occasional social anxiety or workplace stress. It is a daily calculation — a lifelong attempt to appear “normal” in a world built around expectations that often feel invisible and instinctive to everyone else.

The difference between a trend and a lifeline

The conversation around ADHD and autism has become impossible to ignore. More people are seeking diagnoses and openly identifying as neurodivergen, while the rest of the world is attempting to adapt.

Alongside that visibility has come a growing backlash. Are people over-identifying with disorders? Are ordinary personality traits being medicalised? Has neurodivergence become a cultural trend?

Author and ADHD campaigner Ellie Middleton believes those debates often miss something important. “There are almost two conversations that often get logged into one conversation,” she says.

One is the casual misuse of clinical language. Most of us have heard someone describe themselves as “a bit OCD” because they like a tidy kitchen, or “a bit ADHD” because they forgot their keys. Middleton says reducing medical conditions to personality quirks can be dismissive and unhelpful. But she argues this is entirely different from the growing number of people who identify with ADHD or autism while struggling to access a formal diagnosis.

An imperfect solution to an imperfect system

At a time when NHS waiting lists stretch into years and private assessments remain financially out of reach for many, self-identification is often less a trend than a response to a system people cannot easily navigate.

“The vast majority of people that are self-diagnosing,” Middleton says, “is an imperfect solution to an imperfect system.”

For many adults — particularly women and people from minority backgrounds — the problem begins with recognition. Diagnostic criteria for both autism and ADHD were historically shaped around young boys, meaning countless people grew up without seeing themselves reflected in the descriptions they encountered. Many became highly skilled at masking.

Middleton describes how some people are still told they cannot be autistic because they make eye contact, maintain friendships or work in customer-facing jobs. Yet learning to camouflage distress, confusion or overwhelm is often part of the experience itself.

“I think with girls, typically there’s a lot more hidden rules,” she says. “A lot more of the unwritten rules, which for an autistic brain it’s like, ‘What? I don’t understand what I’m doing wrong.’”

The hidden labour of functioning

What emerges from this conversation is a reminder that neurodivergence is not always visible. The colleague who appears organised may be expending enormous energy simply staying afloat. The friend who seems sociable may spend days recovering from the effort of navigating social situations. The employee who struggles to sit at a desk for eight uninterrupted hours may not be lazy or unfocused; they may simply work differently.

And perhaps that is where the wider lesson lies. Middleton understands why some people worry about self-diagnosis, but she believes the debate often overlooks the balance of risk.

The practical consequences of someone incorrectly identifying themselves as autistic or ADHD are, in reality, relatively limited. They don’t get given anything special, there is no funding for them, the pharmacist doesn’t hand them medication on their say-so alone.

“The worst-case scenario of somebody wrongly self-diagnosing is that they’re a bit kinder to themselves,” says Middleton. “They buy a wall planner.”

By contrast, the consequences of remaining undiagnosed can be devastating. “People think that they’re broken or damaged or unlovable or wasted potential,” Middleton says.

Many spend years believing there is something fundamentally wrong with them, without understanding why everyday life seems harder for them than it appears to be for everyone else. Undiagnosed neurodivergence is associated with significantly higher rates of anxiety, depression, addiction and suicidal thinking. “The worst-case scenario of people going undiagnosed is as bad as you can possibly get,” she says.

Why accommodation is not “special treatment”

Middleton also believes the conversation around accommodation is often framed incorrectly. She regularly encounters employers who worry that adjustments for neurodivergent employees amount to “special treatment”. Her response is simple: “If someone in your team is telling you how they’re going to work better,” she says, “why wouldn’t you give them that?”

Whether someone needs noise-cancelling headphones, flexible working hours, more frequent breaks or simply clearer communication, the goal is not preferential treatment. It is creating conditions in which people can function at their best.

Crucially, this idea extends far beyond ADHD and autism. Most people spend at least some part of their lives hiding aspects of themselves in order to fit in. We develop professional personas and soften traits that feel unacceptable. We learn which parts of ourselves seem socially rewarded and which parts feel safer to conceal.

For neurodivergent people, that masking can be particularly exhausting. But the instinct behind it — the desire to belong — is deeply human.

“Everybody would be better off if they were able to be themselves,” Middleton says, “and not have to worry about whatever difference it might be.”

Acceptance does not require understanding

One of the most powerful ideas Middleton returns to is this: “We need to learn to accept, even when you can’t understand.”

Someone without ADHD may never fully grasp why another person struggles to sit in a chair for eight consecutive hours. Someone without autism may never instinctively understand why social situations can feel overwhelming or why unwritten rules can feel impossible to decode.

“I’m working on a different operating system to yours,” says Middleton, “you’re not going to be able to understand it.”

But understanding is not a prerequisite for compassion. “Just because you can’t understand it,” she says, “you should still accept that I’m telling the truth.

“Just because it’s not what I’ve been told is normal,” Middleton says, “that’s not a reason to assume it’s a bad thing.”

Ellie Middleton’s Unmasked (Penguin Life, £11.99) is out in updated paperback on July 2.

Words: Sally Saunders, Images Luke Nugent, Candid Studios