Avid coffee drinker and also happen to have ADHD? Ever wondered whether caffeine might be impacting your symptoms? In this post, we’ll be debunking a few myths about the relationship between caffeine and ADHD, exploring why your morning espresso may make you feel more tired than alert, and sharing a few things to be aware of when consuming caffeine and taking ADHD medication.
For many, coffee is the ultimate wake-up call. It tastes great, sharpens focus, boosts energy, and turns sluggish mornings into something a little more manageable. But for some people with ADHD, each sip of coffee can be a little too soothing, making them feel more tired than before.
Wherever you land on the spectrum, you’re probably well aware that coffee affects the brain. And, along with its links to alertness, some studies even suggest that coffee may have other cognitive benefits, from improved memory and mood to potential long-term brain health perks.
What are the downsides? If overconsumed or taken on an empty stomach, coffee can cause jitteriness, anxiety, and rapid heartbeat. And all of this is due to one very popular naturally occurring chemical compound: caffeine.
Caffeine is a psychoactive drug. In fact, it’s one of the most widely consumed psychoactive drugs in the world. Naturally found in coffee beans, tea leaves, and cacao, caffeine belongs to a class of compounds called xanthines, known for their stimulating effects on the central nervous system. Although it may feel like it, caffeine doesn’t actually create energy itself. Instead, it alters brain chemistry to make you feel more awake.
Its main target? Adenosine. A neurotransmitter that promotes relaxation and drowsiness. Throughout the day, adenosine builds up and binds to receptors, gradually slowing down brain activity. Caffeine blocks these receptors, preventing adenosine from taking effect, which leads to increased alertness.
At the same time, this interference triggers the release of neurotransmitters like dopamine and norepinephrine, which help us to stay focused, motivated, and emotionally balanced.
But the brain adapts. The more caffeine a person consumes, the more adenosine receptors that are produced, meaning higher doses are needed to achieve the same effect. This tolerance can lead to dependence, and when caffeine intake drops suddenly, withdrawal symptoms like headaches and fatigue can set in.
Learn more about our monthly newsletter for neurodiverse professionals
Where does all this caffeine science tie into ADHD? Well, it all starts with the ‘feel-good’ neurotransmitter: dopamine.
Some studies have linked ADHD to dopamine dysregulation in key brain regions responsible for focus, motivation, and impulse control. This is partly why stimulant medications, which increase dopamine and norepinephrine activity, are commonly prescribed. While caffeine isn’t as potent or targeted as these medications, it has a similar effect — it blocks adenosine receptors, indirectly influencing dopamine pathways and boosting norepinephrine levels.
For some people with ADHD, these increased dopamine levels appear to lead to improved concentration and a sense of calm rather than the typical caffeine-induced jitters. Instead of overstimulating the brain, caffeine may help to balance a person’s neurochemical activity, making focus feel more natural. However, its effects vary — what works as a mild cognitive boost for one person might be barely noticeable for another.
Another proposed theory is that caffeine may help people with ADHD by restricting circulation. Caffeine is a vasoconstrictor, meaning it narrows blood vessels, limiting overall blood supply. While the exact mechanism isn’t fully understood, some researchers suggest that this effect on overactive brain regions may help them function more efficiently in people with ADHD.
It’s a misconception that if you have ADHD, you’ll either be bouncing off the walls or automatically feel sleepy after drinking coffee. Other factors like age, weight, hormones, and sex can all have an impact on how you metabolise caffeine. Just as different people have different types of ADHD, not everyone responds the same way to stimulants.
For some people with ADHD, the calming effect of dopamine does appear to work a little too well, making them feel more tired than before. However, if a person’s fatigue is rooted in poor sleep, mental burnout, or ADHD-related energy crashes, caffeine may not be enough to override symptoms, and those issues need to be addressed first.
Read our recent newsletter on navigating ADHD in the workplace
It’s important to figure out how caffeine affects you personally. If you’ve noticed a negative correlation between caffeine and how tired you feel, you may choose to go cold turkey, or you might opt for a different approach, and try experimenting with different amounts or timings.
Try keeping a diary for a week. Track when you drink coffee, how you feel afterwards, and whether it’s helping or making things worse. If caffeine consistently leads to crashes or drowsiness, it might be worth reducing or replacing it with other strategies, like better sleep habits, hydration, or movement.
Regardless of whether you have ADHD or are neurotypical, it’s best to avoid anything over 400 mg of caffeine a day. This is the maximum amount recommended by the FSA and equates to around four cups a day.
As we touched upon earlier, caffeine is a stimulant drug. And since many first-line ADHD treatments like Methylphenidate, Lisdexamfetamine, and Dexamfetamine also happen to be stimulant drugs, those taking ADHD medication should err on the side of caution when combining the two.
Since caffeine acts on the central nervous system, combining it with ADHD medication may intensify unwanted side effects like jitters, increased heart rate, anxiety, and insomnia. Never exceed the recommended amount of caffeine and always consult with your GP if you feel unsure.
As you can see, caffeine affects everyone differently. Since more research is needed into the relationship between caffeine and ADHD symptoms, it’s important to pay attention to your own patterns, so that you can make the best call for yourself. And if you’re taking ADHD medication, always check the box for any drug interactions.
Lastly, don’t forget that it’s not just the caffeine in your favourite foods or beverages that can impact how you feel. Caffeine-containing items like energy drinks and chocolate often contain large quantities of sugar, which can add another layer of unpredictability to your mood and tiredness levels. So, if you’re in the process of exploring your body’s relationship with caffeine, be sure to factor sugar in too.
Our small but mighty team builds leading-edge software that people love. We pride ourselves on a user-led approach to product design. The voice of the customer shapes what we create and that’s exactly how great assistive tech should be made.
