When caffeine and amphetamine ADHD medications combine, their combined effect is more powerful. Caffeine intensifies the effects of amphetamines, so someone taking Adderall would likely feel a stronger impact, including greater side effects.

Caffeine is found in coffee, tea, and chocolate to name a few, and it’s one of the world’s favorite drugs. But what impact does it have on your brain? The right amount of caffeine can help you focus, but too much might make you jittery, anxious, or irritable.

Because caffeine is so prevalent, it’s important to know how it affects individuals with ADHD.

Caffeine is considered a stimulant. It stimulates the body’s central nervous system, and boosts the brain’s production of a neurochemical known as dopamine, which controls the ability to focus and maintain concentration.

This stimulation can cause a person to feel energized and not to feel the effects of fatigue as strongly.

Sometimes the effect can be negative, however. For example, people who have trouble sleeping can experience further sleep disturbances or insomnia due to caffeine.

Reduced sleep

Sleep deprivation can cause ADHD-like symptoms. These include:

  • irritability
  • increased forgetfulness
  • trouble focusing or sitting still
  • difficulty controlling emotions

Sleep deprivation makes these symptoms worse in people with ADHD.

People with ADHD should only use caffeine in the morning and should avoid consumption of coffee, tea, soda, or chocolate in the evening or late at night.

Reduced blood flow to the brain

Caffeine is also a vasoconstrictor. That means it makes blood vessels smaller and reduces blood flow. This reduced blood flow is why caffeine helps headaches.

Amphetamine medications used to treat ADHD also make blood vessels smaller, while increasing blood flow in others.

Although the exact reason is unknown and data is limited, reduced blood flow may help treat ADHD by reducing the activity of brain regions that are overactive, allowing them to better function and cooperate with the rest of the brain.

Dopamine levels in the brain have to be within a very narrow margin in order for a person to be able to focus on their work. But in ADHD, dopamine levels are too low. Stimulant chemicals such as caffeine or amphetamines tend to increase dopamine levels.

For most people, adding stimulants will push dopamine levels too high, causing agitation and anxiety. But for people with ADHD, adding stimulants can get the levels just right.

Some studies have found that caffeine can boost concentration for people with ADHD. Since it’s a stimulant drug, it mimics some of the effects of stronger stimulants used to treat ADHD, such as amphetamine medications.

However, caffeine alone is less effective than prescription medications. There are no studies that suggest that caffeine can be an effective treatment for ADHD.

When caffeine and amphetamine medications like Adderall (amphetamine and dextroamphetamine) combine, they cause an effect called synergy.

Synergy occurs when two drugs have additive mechanisms of action, making their combined effect more powerful. Caffeine intensifies the effects of amphetamines, so a person taking Adderall, for example, would likely feel a stronger impact, including greater side effects.

The FDA defines the maximum safe amount of caffeine for healthy adults as four or more cups of coffee per day, or 400 mg. Too much caffeine may cause:

  • sleeplessness
  • rapid heartbeat
  • irritability
  • anxiety
  • insomnia
  • muscle shakes or tremors
  • upset stomach

Since medication combinations are very hard to control, a person taking both amphetamines and caffeine will also get a double dose of their side effects. Both drugs can cause anxiety, difficultly sleeping, nausea, and stomach pains.

If you’re experiencing anxiety or difficulty sleeping, you may be ingesting too much caffeine. Make sure to always take both your medication and caffeine with food to control stomach pains. Talk to your doctor if nausea persists.

Although emerging research is finding that ADHD has a genetic component, it’s also finding that ADHD is not just one thing. Rather, people with mutations at any number of points in their genetics might get classified with ADHD.

For developing children, some brain regions might develop at different rates than the other regions that regulate them. Because ADHD has different causes, treatments can affect people differently.

Some people find that caffeine helps their ADHD, while others find that it doesn’t offer any benefit at all, or even makes their focus worse. Pay attention to your body and work with your doctor to find out what is best for you.