Overstimulation in ADHD

Overstimulation is what happens when there’s too much sensory input for your brain to handle. It can make you feel overwhelmed, irritable, and uncomfortable. Because the ADHD brain isn’t as equipped to filter out sensory input, you’re more likely to have a lower threshold for the amount of stimuli you can tolerate before becoming overstimulated.

What Does Overstimulation Feel Like?

Overstimulation is a state of feeling overwhelmed by the situation you are in. This might take the form of physical or emotional discomfort and feeling like your brain is frozen or you’re unable to think or process anything that’s happening.

It can also make you irritable, panicked, or stressed, causing you to lash out at your friends or loved ones all while feeling a strong urge to escape the situation.

That awful experience can motivate you to avoid situations that might be overstimulating, like crowded venues, loud concerts, or even bright, sunny days at the beach—a habit that can end up causing you to miss out on bonding with friends and may even hold you back from your professional and personal goals.

What Triggers Overstimulation?

Overstimulation happens when a person surpasses their threshold for sensory input. Everyone, whether or not they have ADHD, has a point beyond which sensory input becomes overwhelming—think of the volume at which sound begins to hurt your ears or the level of brightness that feels blinding.

Some have lower thresholds than others.

For example, if you have sensory issues, your specific sensitivities can quickly cause sensory overload, even at intensity levels that wouldn’t register as excessive for someone without that hypersensitivity.  

For those with touch-based issues, the tags on your clothes or a chair upholstered in a fabric that bothers you can already start to make you feel a little uneasy. Then, when you factor in any other inputs, you’re more prone to overstimulation.

Overstimulation vs. Hypersensitivity

Even though sensory issues can put you at risk of overstimulation, hypersensitivity is not the same as overstimulation.

You might not care about those tags on your clothes or loud noises most of the time, but suddenly, any input is unbearable when you’ve exceeded your threshold.  

Overstimulation in ADHD

If you have ADHD, with or without sensory issues, your brain may be more vulnerable to reaching that point of overstimulation simply because of the way its attentional processes work.

One of the core features of ADHD is inattention. This is often experienced as struggling to make your brain pay attention to the task you want it to pay attention to. In research, it’s often referred to as “poor attentional control” or the impaired ability to filter irrelevant information and inputs.

That impaired filter may be the same underlying issue that makes people with ADHD vulnerable to overstimulation: your brain is paying attention to everything all at once.

For example, in one study measuring this lack of control over attention, subjects with ADHD had 138% more “background noise” in their brain than the control group during a task that simply asked subjects to report what digits appeared on a screen at random intervals.

So that 138% increase compared to the control group suggests that people with ADHD weren’t filtering visual input in order to focus solely on the digits that were appearing on screen. Their brains were trying to pay attention to everything, even though all they needed were the digits.

Another study confirms this with functional magnetic resonance imaging (fMRI) data showing that all regions of the brain associated with sensory processing show elevated activity, even during a resting state when the subject isn’t being asked to perform any tasks.

How I Experience Overstimulation

My own experience lines up with these conclusions. Without medication, it feels like there’s all this “static” in my brain that makes it hard to concentrate or think. When I take my medication, it’s like that static quiets down, and I can finally think clearly. While I’ve never had my brain activity measured, I can imagine the elevated background noise researchers are referring to feels a lot like the static in my brain.

This can make it hard to focus on, say, reading a book because your brain doesn’t give the words on the page any more priority than the sensation of the scratchy texture of the chair you’re sitting in, the sound of the refrigerator humming, the vague constricting feeling of your waistband, or the random objects also in your field of vision while you’re trying to focus on the book.

If your brain is trying to process everything all at once, you might be more vulnerable to overstimulation. Instead of shutting irrelevant input out to avoid overload, it keeps trying to take it all in.

Overstimulation in Autism

Overstimulation is not only a symptom of ADHD; it's often seen in autistic people as well.

People with ADHD and autistic people may display similar signs of hyperactivity when overstimulated, such as being extra reactive to sensory input (i.e., becoming fascinated by a specific object or fixating on a sensation). In addition, overstimulation in both ADHD and autism can lead to emotional and behavioral issues like anxiety, irritability, or anger.

The two diagnoses often co-occur. Research suggests that between 31% and 95% of autistic children show symptoms of ADHD such as inattention, hyperactivity, or impulsivity.

How to Cope With and Avoid Overstimulation

Overstimulation can be uncomfortable. But the good news is that removing yourself from the situation usually lets you calm down quickly. Plus, tricks that help your brain tune out sensory input can help you avoid overstimulation in the first place.

Take a Sensory Break

If you find yourself overstimulated, tell your friends or coworkers that you’re going to step out for a break. Take 5–10 minutes to go somewhere that isn’t overwhelming. While there, you can try some of these techniques to calm your overwhelmed brain:

• Listen to your favorite music
• Pet a dog (or cat, or iguana, whatever pets you have available)
• Take a walk
• Call a friend for a quick chat
• Write through what you’re feeling in a journal

Identify Your Threshold

Everyone has a different threshold for the amount of sensory input they can handle without being overstimulated. Start paying attention when you feel overstimulated to figure out what kinds of sensory input (and what levels of each type) are most likely to overwhelm you.

You can’t control every sensory input you encounter in a day, but knowing your threshold can help you avoid or prepare for situations that could be overstimulating. For example, if you can’t avoid taking the busiest shifts at work, plan a “sensory break” strategy that you’ll be able to do at work, which can help you manage your overstimulation to get through the shift.

Embrace the Power of Fidgeting

While it’s often seen as a sign that you’re not paying attention, research shows that fidgeting actually improves your focus. Improving focus can help you more effectively tune out the irrelevant inputs that can lead to overstimulation.

So honing your personal fidgeting strategy can help ease multiple ADHD symptoms.

If you’re reading or working on something that requires your hands, you could tap your foot, pedal on a stationary bike, or put your feet on a balance board or exercise ball.

Create Optimal Stimulation Environments

If dealing with overstimulation wasn’t hard enough, people with ADHD are also prone to becoming understimulated. So as you find ways to avoid overstimulation, make sure you aren’t confining yourself to an environment that isn’t stimulating enough. Instead, create the right sensory environment.

To do that, distinguish between helpful and unhelpful sensory input. In my case, for example, I’m easily distracted and overwhelmed by environmental noises—cars, birds, people chatting—but absolute silence makes me feel isolated and cut off from the world.

To strike the right balance, I use noise-canceling headphones to listen to enjoyable music without lyrics (to avoid getting distracted by the words in a song). It provides just the right amount of stimulation to avoid feeling bored without tipping over into overwhelm.

Visually, I tend to feel overwhelmed when my office is cluttered or dirty but understimulated if the space is completely empty. My desk can’t be piled up with books and papers but if it’s completely bare, it feels off. I need artwork on the walls, a big window to have a view of the outside, and organized stacks of items on my desk.