Written by Dr. Savannah Muncy, Pharm.D on
July 24, 2021
Reading Time: 5 minutes

Medically Reviewed by our Medical Affairs Team

Written by Dr. Savannah Muncy, Pharm.D on:

Caffeine – a morning cup of fresh, hot coffee, a brewed, iced tea at lunch, a creamy chocolate bar for a midday snack, and a can of ice cold soda at dinner – is the world’s most popular stimulant.1-4

But have you ever wondered the correlation between caffeine and ADHD? How coffee can affect your body and your brain? Have you ever felt the effects of caffeine on your body? And just how much caffeine is too much? We will discuss all of this and more.

Sure, caffeine can certainly help you focus1-4 and make you feel more energized,1,3,4 but consuming too much can make you feel jittery,1,3,4 anxious,1,3,4 and irritable.1,2

Too much caffeine can also cause other unpleasant and potentially dangerous side effects such as a rapid heartbeat,1,3,4 upset stomach,1,2,4 restlessness,4 sleeplessness,1-4 migraines,2,3,4 and tremors.1,3,4

Because caffeine is so popular and widely consumed around the globe, it is very important to know and understand how it can affect people who have ADHD.1

How Does Caffeine Work in the Brain?

Caffeine affects the brain’s chemicals and their receptors.3 It binds to the receptors of a chemical called adenosine.3 When adenosine binds to its receptors, it activates them, slowing down the activities of the nervous system and promoting sleep.3

When caffeine binds to adenosine’s receptors, it blocks adenosine from binding, causing increased wakefulness.3 It also triggers the release of the fight-or-flight hormone, adrenaline, resulting in increased energy and focus.3

How Does Caffeine Stimulate the Body?

Stimulants, like caffeine, boost the brain’s production of dopamine,1-4 a neurochemical that affects the ability to focus and concentrate.1,4 This stimulation can also make you feel more energized.1 However, some unpleasant negative effects may occur:

Reduced Sleep

If you already have trouble sleeping, you may experience further sleep disturbances or even sleep deprivation1 if you consume too much caffeine.

Sleep deprivation can bring on a whole other host of negative effects such as irritability, increased forgetfulness, trouble focusing, and trouble with keeping emotions in check.1 Sleep deprivation can worsen these symptoms in people who have ADHD.1

Reduced Blood Flow to the Brain

Caffeine is a vasoconstrictor. That means it decreases blood flow to the brain by making the blood vessels smaller.1 This reduction in blood flow is the reason caffeine can help headaches.1 ADHD medications such as amphetamine also make blood vessels smaller.1 Caffeine may have similar effects as the common ADHD medications.1

Although we do not know the exact reason, the reduction in blood flow may help improve the symptoms of ADHD by calming down the overactive parts of the brain,1,3 allowing them to better function and communicate with the rest of the brain.1

Caffeine for Concentration

The brain’s dopamine levels must be within a very narrow range in order for a person to be able to properly focus.1 But in people who have ADHD, dopamine levels are too low,1 hence they have trouble with focus and concentration. Some studies have found that caffeine can improve concentration in people who have ADHD.1

Since it is a stimulant, it possesses some of the similar effects as the stronger prescription stimulants used to treat ADHD, such as amphetamines.1 Just because it has some similar effects as prescription stimulant medications, caffeine alone is not as effective.1,3

Mixing Caffeine with Prescription ADHD Medications

When caffeine is mixed with certain ADHD medications like Adderall (amphetamine-dextroamphetamine), they cause an effect known as synergy.1

Synergy happens when two medications that have similar mechanisms of action are combined, making their combined effect(s) even stronger.1

For example, if you drink several cups of coffee with an amphetamine medication, you will likely experience enhanced effects as well as greater side effects such as heart palpitations and sleeplessness.1,3

Therefore, it is important that you talk to your doctor before consuming any caffeine with ADHD medications and ask how you should moderate your caffeine intake.

What Does the Research Say?

So far, we have discussed caffeine’s effect on the brain and the body. We have talked about the synergistic effects on the body when mixing caffeine with ADHD medications. So, does caffeine help the symptoms of ADHD or does it actually worsen them? Let’s see what some of the research has to say.

More often than not, doctors prescribe stimulant medications, like Adderall, to help ADHD patients feel more focused and calm.2 Some “studies show that the caffeine in tea can improve alertness and concentration,”2 making some researchers believe that it may work for people with ADHD as well.

A 2011 study that was published in Medical Hypotheses “proposes that tea consumption may be an effective active treatment for adults [with] ADHD.”5

“A 2013 study published in European Neuropsychopharmacology”4 proposes that caffeine could be a useful treatment [for people who have ADHD], as it appears to normalize dopamine levels [in the brain] and improve attention.4,6

A 2014 review published in the journal J Psychopharmacol called for4 “further investigation of caffeine’s therapeutic potential as a monotherapy or as an adjunctive agent in ADHD.”7

Everyone is Different

New research is finding out that ADHD has a genetic piece as well as other components.1 For children who are developing, some regions of the brain may develop at different rates than others.1 There are different causes for ADHD, and thus, different “treatments can affect people differently.”1 

Some people find that caffeine improves their ADHD while others find that it makes their ability to focus even worse.1 Pay attention to your body and communicate with your doctor to find what may be best for you1 because everyone is different. What works best for one person may not be the best option for another.

Frequently Asked Questions

Having discussed the effects of caffeine on ADHD and how it can affect each person differently, let’s answer some of the most frequently asked questions regarding the use of caffeine in people who have ADHD.

Can caffeine make ADHD worse?

Caffeine helps boost the production of dopamine in the brain,1-4 which can lead to an improved ability to focus and concentrate.1,4

In addition, studies have shown that caffeine may improve alertness, focus, and concentration in people who have ADHD.

However, caffeine still needs to be investigated as a potential monotherapy or adjunct therapy for ADHD patients. Caffeine may worsen your symptoms of ADHD.

For example, “ADHD can cause insomnia and anxiety, which are both side effects of caffeine consumption.”3 Insomnia can lead to sleep deprivation, which can worsen symptoms of ADHD that a person may already be struggling with, like forgetfulness and focus.3

And because caffeine can enhance the effects of ADHD stimulant medications like amphetamine when taken together,1 it is especially important to talk to your doctor before you consume any caffeine with ADHD medications. It is almost important to ask your doctor how to moderate your caffeine intake.

Can you use caffeine to treat ADHD?

Although some studies have shown that caffeine may be effective in improving alertness, focus, and concentration in patients with ADHD, it is not recommended to consume caffeine for the treatment of ADHD.

Caffeine is not as effective as ADHD medications1,3 and therefore, should not replace ADHD medications for the treatment of ADHD.

Talk to your doctor before you consume any caffeine with ADHD medications and ask how you should moderate your caffeine intake.

The Bottom Line of Caffeine and ADHD

Some people find that a cup of coffee helps their ADHD while others find that caffeine makes their ADHD worse. The bottom line is that everyone is different. There is no “one size fits all” when it comes to caffeine and ADHD. 

An Important Point to Remember:

Talk to your doctor and discuss any questions or concerns you may have to find what works best for you. Too much caffeine can cause serious side effects such as heart palpitations and tremors.1,3,4 Before you combine caffeine and ADHD medications, talk to your doctor first and also ask how you should moderate your caffeine intake.

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