Sensory processing and ADHD: overstimulation vs. understimulation

Once upon a time, there was an ADHD brain named Goldilocks.

Many of us ADHDers spend our lives bouncing between burnout and boredom, and it can feel a bit like the fairytale, Goldilocks and the Three Bears. No matter how hard we try to figure out what's “just right” for us, we can still struggle to find the balance between feeling disengaged and overwhelmed.

A lot of this comes down to the way we experience stimulation; more specifically, it's connected to our increased risk of experiencing both overstimulation and understimulation. Before diving into coping mechanisms, let's explore both ends of the stimulation spectrum.


What is overstimulation?

Overstimulation refers to a type of sensory overload; it explains those times when your brain is taking in too much at once. Here's an example you may be able to relate to:

Imagine you’re getting your weekly shopping done at the supermarket. There’s loud music playing, and every time you look down at your phone to check your list, somebody bumps into you with their trolley. There’s endless varieties for each item on your list, so you're forced to make mini decisions for each one. Eventually, feelings of overwhelm start to creep up — you can almost feel your brain overheating like an old laptop with too many tabs open.

That’s overstimulation.

ADHDers have lots of different ways of describing this feeling:

  • “Fried.”
  • "Like my brain is full of static.”
  • “Hot and angry.”
  • "Bees. Bees in my head."
  • "White noise — like an old TV."
  • "Like my head is too full."

But ultimately, these variations are all generally referring to the feeling where your brain just can’t take any more. Any overwhelming situation — such as conflict, rumination, being pressured to make decisions, or receiving an influx of new information — has the potential to be overstimulating.

Signs you might be overstimulated

Everybody has different thresholds for how much input they can handle, and anyone can experience overstimulation — ADHD or not. However, because people with ADHD struggle to filter out any competing stimuli, overstimulation is an especially common experience for neurodiverse brains. Something as simple as someone tapping their pencil in an exam room might be enough to distract and overstimulate us.

This is especially true for those of us ADHDers who are also Autistic, as a hallmark Autistic trait is being hypersensitive to stimuli and experiencing sensory overload.

Here are some signs you might be starting to get overstimulated:

  • You’re irritable and snappy with those around you — especially when they add “complications” to your situation, such as asking you to do an additional task, or talking to you when you're trying to focus.
  • You feel strung-out and oversensitive; on the verge of tears or an angry outburst; the world feels “too much” to cope with.
  • You feel anxious and unable to string thoughts together; like you can’t get your brain to focus on tasks or understand what’s required of you.
  • You have the urge to remove sensory inputs by covering your ears/putting on noise-cancelling headphones, removing tight clothing, or leaving the space you're in and going somewhere you can be alone.

At best, being overstimulated can make us irritable, tired, and unable to focus. At worst (especially when we can’t escape the thing we find overwhelming) it can cause disassociation and extreme emotions. If you regularly experience feeling totally overwhelmed by stimuli, it might be worth looking into the Autistic experience of “meltdowns”.

Coping with overstimulation

Luckily, there are some simple techniques you can try that can minimize overstimulation. Some of these examples include:

1. When feeling stressed or overwhelmed, check in with yourself.

What’s causing it? Is it something solvable (e.g. turning off the music so you can focus, or putting on the air conditioning so you’re more comfortable)? If your overwhelm is coming from an emotion or a task, take 5 minutes to get yourself calmed down before pushing forward.

2. Learn what your common triggers are and work to make them less impactful.

For example, if you notice you’re consistently getting distracted and frustrated at work because of adjacent coworker conversations, invest in a pair of noise-cancelling headphones. If you have a friend that you find emotionally overwhelming, schedule catch-ups with them on days where you don’t have much else going on.

3. Embrace relaxation and recovery.

You can’t brute force your way into getting through overstimulation. You’ll only start to feel better after you let your brain rest and “cool down”. Resting doesn't have to mean doing nothing, either. Try engaging in an activity that you enjoy and find relaxing, such as running or playing video games. Give yourself permission to unwind until your brain starts to feel "normal" again.

Now you know a little more about overstimulation and how to deal with it. But... what about the flip side? What happens when you’re understimulated?

sensory processing spectrum. Illustrates the differences between overstimulation, understimulation, and just right.


What is understimulation?

Understimulation is the opposite of overstimulation; it refers to the times when your brain isn't getting enough sensory input to keep you engaged with your surroundings. Research suggests that people with ADHD get less dopamine from positive stimulation than neurotypicals, which can lead to us feeling understimulated in situations that others are typically comfortable in.

Symptoms of feeling understimulated

Some indicators that you might be understimulated include:

  • Feeling physically hyperactive; like you just want to move, speak, or do *something*
  • Feeling like something “isn’t right”, often manifesting in feeling "flat" or irritable
  • Becoming impatient with those around you; wanting things to happen instantly
  • Being in your “own world” or lost in a daydream
  • Being more combative to people around you; starting arguments over things that normally wouldn’t bother you
  • Fidgeting, often with things like nail-biting, hair-pulling, and skin-picking (also known as body-focused repetitive behaviors or BFRBs), or constantly grazing on food.
  • Feeling unmotivated; like you can’t be bothered to simply meet your own needs
  • Feeling absolutely exhausted; like you need to take a nap, but not feeling any better even with rest

If you’re reading this and thinking, “well, yeah — isn’t that just part of ADHD?” In some ways, yes.


One of the key differences between ADHDers and neurotypicals is that we need a lot more positive stimulation to feel engaged. Some of the hallmark “signs” of ADHD, like distractibility, are more likely to manifest when we’re feeling understimulated. That’s why when we slip into hyperfocus, which is really stimulating for us in a positive way, we’re not as easily distracted and can often work for long periods of time.

Understimulation is generally less intense than overstimulation, but can be just as (if not more) impactful. Being understimulated makes it hard for ADHDers to be present in our day-to-day lives, and it can hinder our ability to carry out our responsibilities.

How to deal with understimulation

Overcoming understimulation can be difficult, but there is a way to simplify it: add more positive stimulation! You can mitigate understimulation by:

  • Doing something with your hands in boring situations, like doodling, chewing gum, or using a fidget spinner
  • Listening to music or podcasts while carrying out a mundane task
  • Embracing physical movement rather than trying to stay still
  • Engaging in something you really enjoy for 5-10 minutes to get your brain engaged before you're in the understimulating situation
  • Body-doubling, where another person keeps you company (either physically or virtually) while you complete a task; integrating more social connections into the non-stimulating setting
  • Finding a way to make the experience new or exciting, such as changing your physical surroundings or trying a new technique to complete the task
  • Setting a time limit for the activity in order to create a false sense of urgency

Finding the right level of stimulation for different tasks is vital for overcoming task inertia and procrastination. If you’re experiencing general understimulation (rather than it being a reaction to a specific task or context), try to include enjoyable activities in your routine.

💡Pro Tip! "Enjoyable activities" in the above context should be something that requires active engagement from your brain, like visiting with a friend or dancing to music, rather than something you can passively absorb without thinking, such as scrolling on your phone. This is obviously easier said than done, but even taking five minutes to do something fun (and engaging) can drastically reduce feelings of understimulation.

Final thoughts

Having ADHD can often make you feel like you’re Goldilocks — endlessly searching for situations that aren’t too much... but also aren’t too little. Take the time to check in with yourself about what might be causing you to feel overstimulated or understimulated.

You might just find a way to navigate your life in a way that feels just right.

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Hayley Alexander is a queer Pākehā writer based in Aotearoa New Zealand, with an interest in neurodiversity, disability and chronic illness. You can read more of her ramblings on her Twitter account: @ADHDAngsty.