ADHD and Autism: Where Do They Overlap?
Imagine two people leaving the same busy gathering earlier than everyone else.
From the outside, there may be very little difference between them. Both have reached a point where staying feels like too much. Both are relieved to step outside into somewhere quieter.
But what was happening for each of them during the evening may have been quite different.
One person may have spent much of the night trying to follow conversations while music played nearby and people moved around the room. Perhaps she was also working out when to speak, keeping track of what somebody meant and taking in the lights, voices and movement around her. As the evening went on, the amount she was processing became increasingly difficult to manage.
For the other person, attention may have been pulled repeatedly from one thing to another. He was following a conversation until somebody laughed loudly nearby, another person walked past or something happening across the room caught his attention. He kept losing the thread and finding it again, while sitting in the same place for so long became increasingly uncomfortable. Eventually, stepping outside gave him movement, space and a break from trying to hold onto everything at once.
Neither of these examples tells us that one person is autistic and the other has ADHD. In real life, the experiences themselves may overlap, and one person may have both ADHD and autism.
What they do show is the limitation of looking at behaviour alone.
From across the room, all we saw was somebody leaving a gathering early. We couldn't see what had made the gathering difficult, what the person was responding to or whether the same kinds of experiences had followed them across other parts of their life.
That matters when we talk about ADHD and autism. They are distinct neurodevelopmental conditions that can occur in the same person, and there are areas where the experiences associated with them can look remarkably similar from the outside.
Understanding the overlap isn't as simple as sorting individual behaviours into an ADHD column and an autism column. Real lives are considerably less tidy than that.
ADHD and autism are distinct conditions
ADHD and autism are both neurodevelopmental, which means their broader patterns emerge during development rather than suddenly appearing for the first time in adulthood.
They are not different versions of the same condition.
ADHD involves a persistent pattern of difficulties relating to attention and/or hyperactivity and impulsivity that affects functioning. Autism involves differences in social communication and interaction alongside restricted or repetitive patterns of behaviour, interests or activities, which can include differences involving routines, movement and sensory experience.
Those descriptions are necessarily broad.
Two people with ADHD can differ considerably in the way attention, impulsivity, restlessness, working memory or emotional regulation shape their lives. Autistic people likewise vary enormously in communication, relationships, sensory experience, interests, routines, movement and support needs.
There is no single ADHD personality, and there is no single autistic personality.
This becomes particularly important when we encounter simplified comparisons online, because a short list of traits can make two highly varied conditions appear much easier to separate than they really are.
No single behaviour belongs exclusively to one explanation
Perhaps you prefer written instructions.
That could be useful because holding several verbal steps in mind is difficult. It might give you additional processing time, reduce ambiguity, make expectations more predictable or allow you to return to information without needing to ask somebody to repeat it.
The preference is real.
Its meaning isn't obvious from the preference alone.
The same is true of leaving a gathering, becoming deeply absorbed in an interest or finding an unexpected change difficult.
A person may leave because sensory input has become overwhelming, because social interaction requires substantial conscious effort, because their attention has been repeatedly redirected, because restlessness has built to an uncomfortable level, because they are anxious or tired, or because several of those things are happening together.
Someone may struggle when plans change because predictability is important to them, because the expected sequence has been disrupted, because they need time to prepare for what comes next or because rapidly reorganising several steps creates a significant executive demand.
The outward behaviour gives us somewhere to begin.
The experience underneath it gives us considerably more information.
This is why online ADHD-versus-autism lists can become misleading
You may have seen comparisons that divide familiar experiences into neat categories.
Seeking novelty points towards ADHD, while preferring routine points towards autism. Being highly social suggests ADHD, while finding social situations difficult suggests autism. One kind of intense focus belongs on one side and another belongs on the other.
The simplicity is appealing, particularly when you are trying to make sense of yourself.
But people don't organise themselves according to comparison charts.
Someone can seek novelty in one part of life while depending heavily on predictability in another. An autistic person may enjoy people deeply and have rich relationships while still finding aspects of social interaction effortful or needing substantial recovery afterwards. Someone with ADHD may find social situations difficult for reasons involving attention, impulsivity, working memory, anxiety, previous experiences or something else entirely.
A behaviour that appears similar can arise within very different developmental patterns.
And sometimes it appears because both conditions are present.
ADHD and autism can occur together
For many years, diagnostic systems made the relationship between ADHD and autism more confusing than it needed to be because the two diagnoses were treated as mutually exclusive.
That is no longer the case.
Current diagnostic frameworks recognise that a person can meet criteria for both ADHD and autism. When that happens, one diagnosis doesn't absorb the other or make it less meaningful.
This matters because a person who already has an ADHD diagnosis may notice experiences that ADHD doesn't seem to explain fully and begin wondering about autism. Equally, an autistic person may recognise longstanding difficulties with attention, impulsivity, restlessness or executive functioning and wonder whether ADHD is also part of the picture.
Sometimes that question leads to further assessment.
Sometimes it remains a question.
Recognition can be useful without needing to become an immediate conclusion.
Deep engagement can look similar while holding a different place in someone's life
Both ADHD and autism are often discussed in relation to intense engagement with particular subjects or activities.
This is another area where the language can become confusing.
People with ADHD sometimes describe periods of very sustained attention, particularly when something is highly interesting, novel or engaging. The informal term hyperfocus is often used for this experience, although it isn't itself a diagnostic criterion and isn't unique to ADHD.
Autistic interests can also involve substantial depth, knowledge and sustained engagement, but reducing them to “autistic hyperfocus” loses important parts of the picture. An interest may provide pleasure, expertise, predictability, connection, regulation or a meaningful way of engaging with the world, and its significance cannot be understood simply by counting the number of hours somebody spends on it.
A person can also be both autistic and have ADHD, in which case trying to assign every episode of deep engagement to one diagnosis becomes even less useful.
The question isn't simply How intensely do you focus?
It is what the pattern looks like across the person's life and what the experience means within that broader picture.
Sensory experiences deserve the same care
Sensitivity to sound, light, texture, smell, temperature or other sensory input is strongly associated with autism and forms part of the diagnostic picture.
Sensory differences are also reported by many people with ADHD.
This can create another tempting shortcut: if someone with ADHD is very sensitive to noise, perhaps that means they must also be autistic.
It doesn't.
A sensory experience can be significant without identifying its cause.
The fuller account might include which kinds of sensory input are difficult or sought out, how longstanding the pattern is, what happens when the environment becomes overwhelming, how much it affects everyday life and what helps.
Other possibilities matter too. Anxiety, migraine, sleep deprivation, physical health and individual variation can all influence how tolerable an environment feels.
Recognition gives us a question.
It doesn't necessarily give us the answer.
Social difficulty is especially difficult to reduce to a checklist
Imagine somebody who frequently loses the thread during group conversations.
Perhaps her attention is repeatedly captured by other conversations, movement around the room or thoughts that occur while somebody else is speaking. She wants to follow what is being said, but keeping the thread active while several things compete for attention is difficult.
Another person may be concentrating intensely on the conversation but consciously working out when to speak, how much detail to give, whether a comment was literal, what somebody's expression means or what response is expected.
From the outside, both people might appear quiet, distracted or slightly out of step with the conversation.
Their internal experiences may be quite different.
Even this comparison is too simple to become a diagnostic rule. Autistic people can also be distracted, and people with ADHD can spend considerable effort monitoring social interactions. Anxiety, language, hearing, culture, trauma, familiarity and many other factors can shape how somebody experiences a conversation.
This is why a careful autism assessment considers social communication as a developmental pattern rather than asking whether somebody currently finds parties awkward.
The same visible moment can carry very different information once we understand what is happening inside it.
Masking can make the picture harder to recognise
Some adults become extremely skilled at managing what other people see.
An autistic person may consciously or increasingly automatically monitor social expectations, rehearse conversations, suppress movements, copy ways of interacting or conceal sensory distress. Someone with ADHD may also develop extensive compensatory strategies, perhaps preparing carefully, suppressing restlessness, monitoring impulsive responses or creating systems that keep difficulties out of sight.
The terminology here requires some caution because masking and camouflaging have a much more established research history in autism than they currently do in ADHD.
Even so, the practical problem for assessment is clear.
What somebody can make themselves look like for a period of time doesn't necessarily reveal how the experience feels or what maintaining that appearance requires.
A person may seem socially confident while consciously working through every interaction. Someone may appear organised because they have built an elaborate system around remembering. Another person may sit still through a meeting while using substantial effort to inhibit movement.
This doesn't mean every effortful social behaviour is masking or every successful adaptation conceals a diagnosis.
It means observable competence shouldn't automatically be treated as evidence that no difficulty exists underneath it.
Recognition in autistic people's experiences can be meaningful
Perhaps you already have an ADHD diagnosis and have begun reading autistic people's accounts.
Something feels unexpectedly familiar.
You recognise the need to recover after certain social situations, the discomfort of sudden changes or a sensory experience you had never realised other people didn't share. You take an autism screener and score higher than you expected.
It is understandable if the pieces begin arranging themselves quickly.
Maybe this explains it.
Recognition matters because it can give us language for experiences that have been difficult to describe.
But recognition and diagnosis are doing different jobs.
A screening questionnaire is designed to identify whether further exploration may be useful. It cannot take a single answer and determine why you answered that way, and it cannot consider your whole developmental and clinical picture.
Perhaps you strongly endorse a question about difficulty returning to something after an interruption. That response tells us something real about your experience. What it doesn't tell us by itself is whether the difficulty relates to autism, ADHD attention and working-memory demands, anxiety, another factor or some combination of these.
The response can be accurate while its meaning remains open.
Screening tools are a beginning, not a verdict
This is worth emphasising because online autism screeners are easy to access and can feel surprisingly definitive when the results seem to confirm something you have already begun wondering about.
Screeners can be useful.
They may help identify experiences worth discussing and can provide language for a conversation with a clinician.
But they aren't designed to establish a diagnosis on their own.
A score is interpreted within a much larger account that includes developmental history, current functioning, the pattern of social communication and interaction, repetitive or restricted behaviours and interests, sensory experiences, other possible explanations and the ways someone may have learned to compensate or mask.
That broader assessment is particularly important when ADHD is already present because there are genuine areas of overlap.
You don't need to dismiss a screening result.
You also don't have to turn it into certainty before the rest of the picture has been explored.
Developmental history helps make sense of the overlap
Because ADHD and autism are both neurodevelopmental, assessment looks backwards as well as at what is happening now.
What were you like as a child?
How did you play and communicate? What did friendships feel like? Were there longstanding sensory experiences, routines, interests, impulsivity, restlessness or difficulties with attention and organisation? What did adults notice, and what might have been less visible because you had already found ways to manage it?
Adult memory is imperfect, and not everybody has parents, reports or childhood records available. A good assessment doesn't depend on one piece of historical evidence.
What matters is building as complete a developmental account as possible.
This is quite different from deciding that a behaviour you noticed last Tuesday belongs to ADHD or autism.
Diagnosis comes from the pattern.
Strengths and enjoyment belong in that account too
Clinical conversations understandably spend a great deal of time on difficulty.
But a fuller account of either ADHD or autism includes more than what is hard.
Perhaps an interest has brought years of pleasure, expertise or connection. Maybe particular sensory experiences are deeply enjoyable rather than overwhelming. A preference for predictability may help you create environments that feel calm and coherent, while spontaneity in another part of life feels energising.
Relationships, humour, curiosity, creativity, knowledge and the things someone genuinely enjoys are part of the person whose difficulties are being assessed.
They aren't evidence against neurodevelopmental difference.
Nor do they need to be transformed into symptoms.
Sometimes understanding a pattern means becoming more precise about what is difficult while leaving room for the parts of the experience the person values.
An autism assessment isn't only about finding another label
Someone who already knows they have ADHD may reasonably wonder what an autism assessment would change.
There isn't medication that removes autism itself, so what is the point of knowing?
For some people, the answer is clarity.
An assessment may help explain longstanding experiences that remain unclear, identify support needs, provide language for communicating with other people or help someone understand why particular environments and demands affect them as they do. Formal diagnosis can also be relevant to accessing some services, adjustments or supports, although eligibility varies considerably.
For someone else, assessment may not feel necessary or accessible.
Cost, waiting lists and availability of clinicians with appropriate adult experience can all matter. Some people decide that understanding their own patterns and making useful adjustments is enough for the time being.
There isn't one correct decision.
If assessment is something you are considering, a useful question may be less Do I need to prove that I am autistic? and more What am I hoping an assessment might help me understand or make possible?
Adult assessment needs to look beyond old stereotypes
Some adults reach midlife before autism is considered.
There are many possible reasons for this. Historical understandings of autism were narrower, and presentations that didn't resemble familiar stereotypes were easier to miss. Some people also developed ways of compensating or camouflaging that made differences less obvious to other people.
Girls and women have been particularly important in this conversation because research and clinical understanding have increasingly recognised that autism may be overlooked when presentations don't match historically male-dominated expectations.
That doesn't mean women have a separate form of autism, nor that masking automatically explains every late diagnosis.
It does mean that adult assessment needs enough breadth to consider varied developmental presentations rather than relying on whether somebody resembles an outdated picture of an autistic child.
You don't need to make ADHD and autism compete
Perhaps this is the most useful thing to hold onto.
Once you begin trying to understand overlapping neurodevelopmental experiences, it can feel as though every trait needs an owner.
Is my need for quiet ADHD or autism?
What about the way I prepare for conversations?
The subjects I become absorbed in?
The way an unexpected change can throw me?
Sometimes assessment will help clarify how particular experiences fit within a broader diagnostic picture.
Sometimes the most accurate answer to an individual moment will remain uncertain.
And if both conditions are present, trying to separate every part of yourself into ADHD and autism may not even be particularly meaningful.
A diagnosis describes a pattern.
It doesn't assign ownership of every human experience.
If you are wondering whether autism may be part of your picture
You don't need to arrive at an assessment already knowing the answer.
You can begin with what you have noticed.
Perhaps there are experiences that don't feel fully explained by ADHD, longstanding sensory patterns, aspects of social interaction that require considerable conscious effort, a strong relationship with predictability or interests that hold a particular place in your life.
You can describe what happens outwardly and what the same moment feels like internally. It can also be useful to think about how long the pattern has been present, where else it appears, what changes it and what helps.
A GP or appropriately qualified health professional can help you understand the assessment pathway where you live. If you are seeking an adult autism assessment, it can be worth asking about the clinician's experience with adults and with varied or camouflaged presentations.
You aren't required to prove your case before asking the question.
And you don't need to dismiss the question simply because ADHD might also explain some of what you recognise.
Sometimes “I don't know yet” is useful information
Finding an explanation after years without one can create an understandable hunger for certainty.
Once ADHD makes one part of your life clearer, you may want the remaining pieces to fall into place just as decisively.
But understanding yourself doesn't always happen by assigning every experience to the correct category.
Sometimes it comes from describing the experience more completely.
This is what other people can see.
This is what happens for me underneath it.
I remember something similar when I was young.
This is where it becomes easier.
This is what helps.
Those details may eventually contribute to an autism assessment. They may deepen your understanding of ADHD, reveal another explanation entirely or simply give you better language for something that matters to you.
Recognition doesn't become meaningless because you haven't reached a conclusion.
Sometimes it is the beginning of a better question.
A moment to wonder
Think of an experience you have been tempted to place firmly into an ADHD or autism box.
If you leave the label aside for a moment, what else can you describe about it?
Perhaps there is something about what the experience feels like internally, when you first remember it, the situations in which it appears, what makes it harder or easier, or what the experience helps you do.
You may end up with a clearer question rather than a clearer answer.
For now, that can be enough.
Keep exploring
There’s more to explore across Through the Disconnect, from understanding ADHD and life after diagnosis to masking and making sense of your experience.
References
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Hours, C., Recasens, C., & Baleyte, J. M. (2022). ASD and ADHD comorbidity: What are we talking about? Frontiers in Psychiatry, 13, 837424.
Rong, Y., Yang, C. J., Jin, Y., & Wang, Y. (2021). Prevalence of attention-deficit/hyperactivity disorder in individuals with autism spectrum disorder: A meta-analysis. Research in Autism Spectrum Disorders, 83, 101759.
Lai, M.-C., Lombardo, M. V., Ruigrok, A. N. V., et al. (2017). Quantifying and exploring camouflaging in men and women with autism. Autism, 21(6), 690–702.
Hull, L., Mandy, W., Lai, M.-C., et al. (2020). Development and validation of the Camouflaging Autistic Traits Questionnaire (CAT-Q). Journal of Autism and Developmental Disorders, 50, 819–833.
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