Too Much, Not Enough, and Somehow Both: Understanding Sensory Processing in AuDHD

By Tim Aiello, MA, LPC, NCC, ADHD-CCSP, ASDCS

Sensory issues are usually talked about as an autism thing.

Bright lights are too bright. Sounds are too loud. Certain fabrics feel unbearable. Someone cuts the tag out of every shirt they own and suddenly everyone starts wondering if they are autistic.

That picture is not necessarily wrong, but it is incomplete.

We now have pretty solid evidence that sensory processing differences are common in ADHD too. And when someone has both ADHD and autism, commonly referred to as AuDHD, the sensory experience can become even more complicated.

Sometimes the nervous system wants less.

Sometimes it desperately wants more.

Sometimes, somehow, it wants both at exactly the same time.

That last part is where AuDHD gets particularly interesting.

Sensory Processing Is More Than Being “Sensitive”

When people hear the words sensory issues, they usually picture hypersensitivity, meaning someone experiences sensory input more intensely than other people.

That is only one piece of sensory processing.

A person can experience hyperreactivity, where certain sensations register very strongly. They can experience hyporeactivity, where sensory information does not register as readily. They can experience sensory seeking, where the nervous system actively looks for additional stimulation. They can also experience sensory avoidance, where the person attempts to reduce or control sensory input.

And one person can experience all of these.

Research involving autistic adults has found exactly that. Rather than fitting neatly into one category, autistic adults frequently describe combinations of hyperreactivity, hyporeactivity, and sensory seeking across different senses and situations (MacLennan et al., 2022).

Sensory processing also includes much more than the traditional five senses. We are processing information from several systems at once, including:

• Vision, sound, touch, taste, and smell

• Vestibular processing, which involves movement, balance, and our relationship to gravity

• Proprioception, our sense of where our body is in space and how our muscles and joints are moving

• Interoception, our awareness of internal body signals such as hunger, thirst, temperature, heart rate, bladder signals, fatigue, and other internal sensations

  
  

That means sensory differences can show up in ways that do not immediately look sensory.

Someone may constantly move their legs. Someone else may not realize they are hungry until they suddenly feel terrible. Another person might love extremely loud music but become genuinely distressed by two people talking at once nearby.

Sensory processing is really about how the brain notices, prioritizes, organizes, and responds to information.

And that is where ADHD and autism begin overlapping in some fascinating ways.

Sensory Processing in Autism

Sensory differences are formally recognized as part of autism.

The DSM 5 TR includes hyperreactivity, hyporeactivity, and unusual interest in sensory aspects of the environment within the diagnostic criteria for autism. Examples can include strong reactions to sounds or textures, reduced responses to pain or temperature, fascination with visual stimuli, or repeatedly seeking particular sensory experiences.

But even within autism, there is no single autistic sensory profile.

One autistic person may be extremely sensitive to sound and relatively unaffected by touch. Another may seek intense pressure while avoiding certain food textures.

Someone may love flashing concert lights while finding fluorescent office lighting unbearable.

Research with autistic adults reinforces how individualized these experiences are. MacLennan and colleagues found that autistic adults described combinations of sensory hypersensitivity, hyposensitivity, and seeking, along with significant differences in how much control, context, and tolerance affected their experience.

This matters because sensory processing is not simply about the physical intensity of a sensation.

Context matters. Predictability matters. Control matters.

The music you chose to blast through your headphones can feel amazing.

The television someone else turned on while you are trying to concentrate might feel unbearable.

Technically, both involve sound.

Neurologically and psychologically, they are very different experiences.

There is also growing research examining differences in habituation, sensory gating, and predictive processing in autism. In simple terms, the brain normally learns to decrease its response to repetitive or irrelevant sensory information. Your refrigerator may sound loud when you first walk into the kitchen, but several minutes later you barely notice it.

Some autistic people appear to habituate differently to certain sensory information, meaning the brain may continue registering input that another person's brain gradually pushes into the background. Current evidence is not perfectly consistent, however, and sensory gating research across neurodevelopmental conditions remains an evolving field rather than a finished explanation.

That distinction is important. Autism research has moved well beyond the idea that autistic people are simply “too sensitive.”

The sensory system itself appears to process information differently.

ADHD Has Sensory Differences Too

For a long time, sensory issues in ADHD received considerably less attention.

That is changing.

A major 2025 systematic review and meta analysis examined 30 studies involving 5,374 participants with ADHD. Compared with control groups, people with ADHD showed significantly higher levels of sensory sensitivity, sensory avoidance, sensory seeking, and low sensory registration.

In other words, ADHD was associated with differences across essentially every major sensory processing pattern researchers examined.

Earlier adult research found similar results.

Kamath and colleagues found that adults with ADHD reported greater sensory sensitivity, sensation seeking, and low sensory registration than adults without ADHD, even after researchers accounted for internalizing symptoms such as anxiety (Kamath et al., 2020).

Bijlenga and colleagues also found both sensory hypersensitivity and hyposensitivity among adults with ADHD, even after autistic traits were taken into consideration (Bijlenga et al., 2017).

That last point is especially important.

We cannot simply assume that sensory issues in someone with ADHD secretly mean they are autistic.

ADHD itself appears capable of producing significant sensory differences.

The difference is that sensory reactivity is currently part of the diagnostic criteria for autism, while it is not part of the diagnostic criteria for ADHD.

The research, however, increasingly suggests clinicians should probably be asking ADHD patients about sensory processing anyway. The authors of the 2025 meta analysis specifically concluded that sensory processing should be systematically explored when evaluating both children and adults with ADHD.

So What Happens When Someone Has Both?

This is where we need to be careful.

There is considerably more research examining sensory processing in autism alone and ADHD alone than there is research specifically examining people with both, especially AuDHD adults.

So we do not currently have enough evidence to say there is one scientifically established “AuDHD sensory profile.”

What we can say is that the research examining combined autism and ADHD suggests the interaction may create a sensory experience that is not adequately explained by simply looking at either diagnosis in isolation.

A 2024 study compared children with autism, ADHD, combined autism and ADHD, and typically developing children. The combined group showed particularly pronounced sensory processing differences as well as greater executive functioning difficulties. Sensory differences in the combined group were also more closely connected with emotional regulation difficulties in some areas (Huang et al., 2024).

Earlier research has shown similar patterns. Sanz Cervera and colleagues compared autism, ADHD, combined autism and ADHD, and typically developing groups. In the home environment, the combined group showed the greatest overall sensory difficulties. The researchers also found some differences in which sensory domains appeared most affected across diagnoses.

These studies were conducted with children, so we should not automatically assume every finding translates directly into adulthood.

But they support something clinicians working with AuDHD adults frequently need to consider:

Two neurodevelopmental profiles can interact rather than simply sit beside each other.

And sometimes their sensory demands seem to pull in opposite directions.

The AuDHD Sensory Push and Pull

One of the clearest examples involves stimulation.

ADHD is frequently associated with sensation seeking. Some people with ADHD concentrate better when they are moving, listening to music, fidgeting, chewing something, pacing, changing positions, or otherwise increasing sensory stimulation.

Research comparing university students with ADHD and autistic students actually found significantly greater sensation seeking in the ADHD group, although the groups were similar across many other sensory measures (Clince et al., 2016).

Autistic sensory processing, meanwhile, may involve extremely strong preferences regarding the type, intensity, predictability, and controllability of sensory input.

Put those together and things can get weird.

An AuDHD person might need music playing in order to concentrate but be unable to concentrate if someone nearby is having a conversation.

They might love a packed concert but hate a crowded grocery store.

They might seek very loud music but become overwhelmed by a vacuum cleaner.

They might need constant movement while also becoming visually overwhelmed by everyone else moving around them.

They may crave novelty because their ADHD brain is becoming understimulated while simultaneously needing predictability because unexpected sensory input is exhausting.

None of those things are actually contradictions.

The nervous system is not simply asking, “How much stimulation is there?”

It may also be asking:

What kind of stimulation is this? Did I choose it? Was I expecting it? Can I control it? Is it meaningful? Do I have enough cognitive capacity left to process it?

That is a much better way to understand sensory processing.

When You Can Be Hypersensitive and Hyposensitive at the Same Time

Another confusing part of AuDHD is that a person can appear extremely sensitive in one moment and completely unaware of sensory information in another.

For example, someone may hear a faint electrical hum across the room but completely miss that someone has been calling their name.

They might notice the smallest wrinkle in their sock but fail to notice how tense their shoulders have become.

They may become overwhelmed by a subtle smell while simultaneously seeking extremely spicy food.

They might experience physical discomfort intensely once they notice it but take a surprisingly long time to notice that discomfort in the first place.

Research increasingly recognizes that sensory sensitivity and low sensory registration are not opposites that cancel each other out. Both occur in ADHD, autism, and combined presentations.

Attention probably contributes to some of this complexity.

The brain is receiving an enormous amount of information at any given moment.

Attention helps determine what enters conscious awareness and what remains in the background. ADHD affects attention allocation and inhibition, while autism can affect sensory prioritization, habituation, and the way attention becomes allocated to particular stimuli.

The end result can be a nervous system that notices everything and nothing, depending on what has captured attention.

That sentence sounds ridiculous until you have lived it.

Then it makes perfect sense.

Interoception Deserves Its Own Conversation

Interoception is often discussed within neurodivergent communities because many people describe difficulty recognizing internal body signals.

Someone may not notice hunger until they are suddenly shaky and irritable. They may forget to drink water for several hours. They may not recognize that they need the bathroom until the signal becomes urgent. They might recognize anxiety as a physical sensation long before they consciously recognize the emotion connected to it.

These experiences are real, but the research here deserves some nuance.

Interoception is not one single ability. Researchers measure internal awareness in multiple ways, including subjective awareness, attention to body sensations, heartbeat detection, confidence about internal sensations, and other physiological tasks.

A 2025 systematic review and meta analysis of interoception in autism found inconsistent results. Autistic adults did not consistently show impaired cardiac interoceptive accuracy compared with nonautistic adults, and findings across other areas of interoception varied considerably.

So while differences in interoceptive experience are absolutely worth exploring with neurodivergent people, it is too simplistic to say, “Autistic people have poor interoception.”

Science has not established that.

The lived experience may be much more complicated than a single laboratory task can capture.

Sensory Overload Is Not Just “Too Much Noise”

Sensory overload is often pictured as one obnoxiously loud sound causing someone to cover their ears.

Sometimes that happens.

More often, especially in adults, overload is cumulative.

The lights are bright.

Three conversations are happening nearby.

Your shirt has been rubbing against your neck for two hours.

You have been switching between tasks all day.

Your phone keeps vibrating.

You have not eaten enough.

Someone asks you another question.

Then suddenly the sound of someone chewing feels like an act of war.

The chewing probably did not create the entire reaction.

It was simply the final piece of input that the system could no longer comfortably process.

This becomes especially relevant in AuDHD because executive functioning and sensory processing appear to interact.

The 2024 study by Huang and colleagues found relationships between sensory processing and executive functioning across autism, ADHD, and especially the combined group. Their findings also suggested greater emotional regulation difficulties in the combined group were associated with more pronounced sensory differences.

Research in autism more broadly has also found meaningful relationships between sensory processing differences and internalizing and externalizing difficulties. A 2024 systematic review and meta analysis involving 63 studies and more than 11,000 autistic participants found that higher levels of sensory processing differences were associated with greater emotional and behavioral difficulties, particularly with auditory, visual, and tactile sensitivities.

This does not mean sensory issues “cause” every emotional reaction.

It means that sensory load is part of the equation.

Sometimes what looks like irritability is overload.

Sometimes what looks like avoidance is regulation.

Sometimes what looks like being dramatic is someone operating with almost no sensory bandwidth left.

Why AuDHD Sensory Needs Can Look Inconsistent to Other People

One of the most frustrating experiences for many neurodivergent adults is hearing some version of:

“But that didn't bother you yesterday.”

That may be completely true.

Sensory tolerance is not necessarily static.

Sleep, stress, anxiety, cognitive workload, physical discomfort, social demands, hunger, control over the environment, and how much sensory input someone has already processed can all influence how manageable additional stimulation feels.

Autistic adults themselves have described sensory tolerance and sensory management as highly dependent on context and control.

This is also why someone may tolerate a loud concert for three hours and struggle with twenty minutes inside Target the following afternoon.

Those environments are not neurologically equivalent.

One may involve predictable music that the person loves, chosen sensory stimulation, rhythmic input, focused attention, and positive anticipation.

The other may involve fluorescent lighting, unpredictable movement, overlapping conversations, carts squeaking, announcements, visual clutter, decision making, navigation, social interaction, and executive functioning.

Decibels alone cannot explain sensory load.

Regulation Sometimes Means Less Stimulation, and Sometimes It Means More

This is probably one of the most important things to understand about AuDHD.

We sometimes assume regulation means creating a quiet room, turning off the lights, and removing stimulation.

That is excellent regulation for some people at some times.

For an understimulated ADHD nervous system, however, reducing everything may actually make concentration or regulation harder.

Sometimes regulation means quiet.

Sometimes it means heavy music.

Sometimes it means lying underneath a weighted blanket.

Sometimes it means pacing around the room.

Sometimes it means wearing headphones.

Sometimes it means taking the headphones off because suddenly they feel like too much pressure around your ears.

The goal should not be to create a universally “low sensory” environment.

The goal is to help someone understand their sensory profile well enough to adjust the environment in either direction.

That may mean reducing unpredictable sound while increasing movement.

It may mean dimming lights while adding deep pressure.

It may mean allowing someone to fidget during a conversation because that additional sensory input actually helps them process what is being said.

This is why individualized accommodations generally make more sense than rigid sensory rules.

A Better Way to Ask About Sensory Issues

When I am trying to understand someone's sensory experience, I think “Are you sensitive to sensory input?” is actually a pretty weak question.

A lot of people will say no.

Then you start asking better questions.

What sounds make it impossible for you to think?

What sensations do you actively seek out?

What textures make your body recoil?

Do you need movement in order to concentrate?

Are there sensations other people seem to notice before you do?

Do certain environments exhaust you even when you cannot explain why?

What happens when several sensory inputs occur at the same time?

Do you notice when you are hungry, thirsty, tired, tense, hot, or cold?

What sensory experiences actually make you feel better?

That last question matters just as much as the others.

Sensory processing is not only about discomfort. Neurodivergent people can also experience extraordinary sensory pleasure. Music can feel enormous. A certain texture can be unbelievably calming. Deep pressure can create an almost immediate sense of settling. Movement can wake the brain up. A familiar smell can feel grounding. A perfectly balanced sensory environment can feel incredibly safe.

Sensory differences create vulnerability to overload, but they can also create incredibly rich experiences of the world.

The Goal Is Not to Become Less Sensitive

There has historically been a tendency to approach sensory differences as something that needs to be corrected.

I think that misses the point.

There are certainly times when sensory processing differences interfere significantly with eating, sleeping, working, relationships, medical care, community access, or everyday functioning. Those situations deserve support.

But support does not automatically mean teaching someone to tolerate increasingly uncomfortable sensations.

Sometimes the healthier intervention is an accommodation.

Wear the headphones.

Cut the tag out.

Dim the lights.

Use the same mug every morning.

Move while you work.

Take ten minutes alone after the meeting.

Choose the seat at the edge of the restaurant.

Bring the safe food.

Stop forcing yourself to stay in an environment after your nervous system has already told you it is done. We should certainly help people expand flexibility when doing so genuinely improves their lives. But there is a difference between building flexibility and repeatedly teaching someone to ignore their own nervous system.

Understanding the AuDHD Sensory System

ADHD and autism overlap in many areas, but they are not interchangeable neurotypes.

The same is true of sensory processing.

Autistic people can experience hyperreactivity, hyporeactivity, sensory seeking, sensory avoidance, differences in habituation, and strong sensory preferences.

People with ADHD can also experience sensory sensitivity, low registration, avoidance, and sensation seeking, even in the absence of autism.

When both occur together, the result may be a particularly dynamic sensory system, one that sometimes seeks stimulation and sometimes needs immediate relief from it.

That can make AuDHD sensory needs look inconsistent.

They are not necessarily inconsistent.

They are context dependent.

The better question is usually not:

“Why does this bother me when that doesn't?”

It is:

“What is my nervous system trying to manage right now?”

Once we begin looking at sensory processing that way, a lot of behaviors that once seemed random start making considerably more sense.

And for many AuDHD adults, simply understanding that pattern can be powerful.

You stop asking why you cannot just tolerate what everyone else seems to tolerate.

You start noticing what your nervous system actually needs.

That is not giving in to sensory issues.

That is learning how your brain works.

Research Sources

American Psychiatric Association. (2022). Diagnostic and statistical manual of mental disorders (5th ed., text rev.). American Psychiatric Association Publishing.

Bijlenga, D., Tjon Ka Jie, J. Y. M., Schuijers, F., & Kooij, J. J. S. (2017). Atypical sensory profiles as core features of adult ADHD, irrespective of autistic symptoms. European Psychiatry, 43, 51–57. https://doi.org/10.1016/j.eurpsy.2017.02.481

Chen, Y., Xi, Z., Saunders, R., Simmons, D., Totsika, V., & Mandy, W. (2024). A systematic review and meta-analysis of the relationship between sensory processing differences and internalising/externalising problems in autism. Clinical Psychology Review, 114, 102516. https://doi.org/10.1016/j.cpr.2024.102516

Clince, M., Connolly, L., & Nolan, C. (2016). Comparing and exploring the sensory processing patterns of higher education students with attention deficit hyperactivity disorder and autism spectrum disorder. American Journal of Occupational Therapy, 70(2), 7002250010p1–7002250010p9. https://doi.org/10.5014/ajot.2016.016816

Huang, Z., Wang, F., Xue, L., Zhu, H., & Zou, X. (2024). Relationships between sensory processing and executive functions in children with combined ASD and ADHD compared to typically developing and single disorder groups. Brain Sciences, 14(6), 566. https://doi.org/10.3390/brainsci14060566

Jurek, L., Duchier, A., Gauld, C., Hénault, L., Giroudon, C., Fourneret, P., Cortese, S., & Nourredine, M. (2025). Sensory processing in individuals with attention-deficit/hyperactivity disorder compared with control populations: A systematic review and meta-analysis. Journal of the American Academy of Child & Adolescent Psychiatry, 64(10), 1132–1147. https://doi.org/10.1016/j.jaac.2025.02.019

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