Caffeine is a psychoactive drug that can cause or exacerbate anxiety and other stress-related signs and symptoms in many ways. Learn what you can do.
Caffeine is the world’s favorite mood-altering drug.
This central nervous system stimulant is found in the most popular beverages such as coffee, tea, energy drinks, and many kinds of soda.
People universally love caffeine for the way it makes them feel — confident, alert, focused, and productive.
But caffeine, especially in people who are sensitive to it, can significantly contribute to anxiety and related conditions and symptoms including insomnia, irritability, racing heart, heart palpitations, and even full-blown panic attacks. (1)
If you ever experience any of these signs or symptoms, here are 15 things you should consider before reaching for your next caffeinated drink.
1. Caffeine increases stress hormones
Most people with anxiety would agree they have too much stress in their lives and caffeine adds to the burden.
Caffeine acts much like stress, increasing heart rate, blood pressure and levels of stress hormones.
2. Caffeine affects neurotransmitter balance
Caffeine achieves many of its effects by blocking activity of adenosine, a neurotransmitter that makes us tired and sleepy.
By increasing the brain chemicals dopamine and acetylcholine, caffeine gives us feelings we seek — increased motivation, productivity, and brain power. (4)
But for those with anxiety, there is a downside.
Caffeine also inhibits the calming neurotransmitter GABA. (5)
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GABA puts the brakes on brain activity when needed and has been characterized as “nature’s Valium.”
It’s essential for feeling happy and relaxed and low GABA is associated with anxiety and panic attacks. (6)
Serotonin is the brain chemical tied closely to happiness.
3. Caffeine causes insomnia
One of the most common side effects of both anxiety and caffeine consumption is insomnia.
In fact, caffeine-induced sleep disorder is a recognized mental disorder. (9)
If anxious thoughts make you restless at night, caffeine can compound the problem.
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Caffeine particularly decreases sleep stages 3 and 4 during which some of the most deep, restorative sleep takes place. (10)
Getting adequate sleep is one of the most important things you can do for brain health and mental well-being.
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Keep in mind that caffeine can linger in your system for up to 14 hours, so any caffeine you consume from midday on really can keep you up at night. (14)
4. Some people are genetically sensitive to caffeine
We all know people who can drink a pot of coffee after dinner and sleep like a rock.
If you have anxiety, you probably aren’t one of them.
The difference may be in your genes.
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Some people are genetically predisposed to being more or less sensitive than average to caffeine. (15)
Those hypersensitive to caffeine take longer than average to metabolize it and can experience anxiety, jitters, and insomnia from as little as 100 mg, the amount found in just five ounces of coffee.
5. Caffeine may cause reactive hypoglycemia
Hypoglycemia occurs when your blood sugar drops too low.
A low blood sugar attack can leave you feeling jittery, sweating, heart pounding, irritable, and confused — a lot like an anxiety attack.
While caffeine generally raises blood sugar levels in people with diabetes, whether caffeine truly lowers blood sugar levels in hypoglycemics is a matter under debate. (16)
This occurs when the symptoms of low blood sugar are experienced even though actual blood glucose levels remain normal.
If you suspect that your low blood sugar is exacerbated by caffeine, try going without it and notice how you feel.
6. Caffeine can increase anxiety when taken with many medications
Caffeine is so much a part of our culture, it’s easy to forget that it’s a psychoactive drug.
Consequently, it doesn’t always mix well with other drugs.
Drugs.com currently lists 84 medications that should not be taken along with caffeine.
Sometimes caffeine enhances the effects of some drugs — that’s why it’s often added to over-the-counter painkillers.
And sometimes caffeine undermines the effectiveness of medications.
Anti-anxiety medications, sleeping pills, and lithium for bipolar disorder fall into this category.
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Pharmacist Suzy Cohen reveals some alarming interactions between caffeine and prescription drugs in her book Drug Muggers: Which Medications Are Robbing Your Body of Essential Nutrients–and Natural Ways to Restore Them.
Caffeine can cause tremors, panic attacks, and insomnia when taken with antidepressants that are SSRIs (selective serotonin re-uptake inhibitors).
Caffeine should be avoided when taking breathing medications that contain the stimulant xanthine.
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When taken together, they can cause anxiety as well as dangerous heart pounding, shortness of breath, and arrhythmia.
When caffeine is used with ADHD medications like Adderall and Ritalin, it increases nervousness, irritability, insomnia and heart rhythm abnormalities.
7. Added caffeine is an unregulated, synthetic chemical
Coffee and various teas, including green tea, matcha, and yerba mate, naturally contain caffeine.
But the caffeine found in sodas, energy drinks, energy gel packs, and caffeine pills and powders is usually not extracted from tea leaves or coffee grounds — that would be prohibitively expensive.
The demand for added caffeine has outstripped natural caffeine production since World War II.
Added caffeine is synthetically manufactured in pharmaceutical plants from chemical precursors like urea and chloroacetic acid.
It usually is made in China or sometimes India or Germany.
Journalist and self-proclaimed caffeine addict Murray Carpenter, author of Caffeinated: How Our Daily Habit Helps, Hurts, and Hooks Us, traveled to China to check out the world’s largest caffeine plant while doing research for his book.
It was not the high-tech facility he imagined.
Here’s how he described the plant in his book: “… half the windows were smashed, and rags streamed out. Bags of stockpiled chemicals sat inside the broken first-floor windows. The place reeked — a chemical stench to make you gag — and a tall rusty tank leaked a tarry sludge.”
If you drink soda or energy drinks, you’ve almost certainly consumed caffeine produced there.
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Lastly, don’t be too impressed if you see the words “naturally caffeinated” on a product label.
Unscrupulous manufacturers aren’t above ignoring labeling requirements and using the synthetic version anyway. (19)
Natural caffeine and synthetic caffeine are technically identical but can be told apart using carbon dating. (20)
Synthetic caffeine registers as “older” since it’s made from fossil fuels.
Oddly, synthetic caffeine can exhibit another telltale sign — sometimes it glows. (21)
8. Caffeine linked to mental disorders
It’s been recognized for decades that the symptoms of too much caffeine are very similar to those of many psychiatric disorders.
Too much caffeine can even create symptoms of anxiety in a healthy person that are indistinguishable from those experienced by anxiety disorder sufferers.
Some psychiatrists recommend that routine psychiatric assessments should include examining caffeine consumption since removing caffeine can be more beneficial than adding an anti-anxiety drug.
Caffeine use has been linked to mental disorders of all kinds including anxiety, panic, depression, sleep, and eating.
Taking schizophrenic patients off caffeine improved their anxiety, irritability, and hostility. (22)
Going back as far as 1987, it’s been recommended that “Decaffeinated beverages should be provided on psychiatric wards.”
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9. Caffeine causes at least four recognized mental disorders
The latest edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the American Psychiatric Association’s standard guide of mental disorders, recognizes four caffeine-induced disorders:
- caffeine addiction
- caffeine intoxication
- caffeine-induced anxiety disorder
- caffeine-induced sleep disorder
It’s only a matter of time before caffeine withdrawal joins their ranks.
The World Health Organization recognizes caffeine addiction as a real disorder and numerous studies conclude that some caffeine users can become genuinely addicted. (23)
10. It’s easier than ever to overdo caffeine consumption
There are more ways to consume caffeine than ever before.
You expect to find it in coffee, tea, chocolate, and cola soda but it’s also hidden in prescription drugs, over-the-counter painkillers, non-cola drinks, vitamin waters, brain tonics, and even in vitamins and herbal supplements. (24)
The amount of caffeine in energy drinks can be deceiving since some of the serving sizes are so small.
5-Hour Energy Shot contains a jaw-dropping 100 mg per ounce.
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Another problem is that labels aren’t always accurate.
Sunkist orange soda listed 41 mg on its label, but in fact was found to have almost six times as much caffeine at 240 mg per bottle.
Caffeine’s effects are consistently underestimated but here’s what escalating amounts of caffeine can do:
- 1/64 teaspoon will give you a subtle boost
- 1/16 teaspoon (the amount in 12 oz of coffee) can lead to addiction
- 1/4 teaspoon causes acute anxiety
- 1 tablespoon is enough to kill an adult
You’d have to drink 50 cups of coffee at once for it to be lethal, making it virtually impossible to drink yourself to death with naturally occurring caffeine.
But now pure caffeine pills and powder can easily and inexpensively be purchased online, making caffeine overdose a reality.
11. Caffeine robs your brain of essential nutrients
Caffeine excretes nutrients from your body, some of which are particularly important for your brain health and mood.
Caffeine depletes magnesium, a mineral that has such profound effects on your mental well-being it’s been called the “original chill pill.” (27)
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Dr. Carolyn Dean, author of a bestselling book on magnesium, states emphatically that “Hands down, bar none and without a doubt, the top supplement for anxiety is magnesium and in my experience, if it doesn’t work that means you haven’t taken enough.” (30)
Caffeine also robs you of the B complex vitamins — the “anti-stress vitamins.”
Anxiety is a common sign of B vitamin deficiency. (31)
Taking extra B vitamins can address imbalances between GABA, serotonin, dopamine, and epinephrine that contribute to anxiety. (32)
12. Caffeine might make your brain supplement useless
When you are anxious, blood flow to the brain is already reduced and caffeine can reduce it further. (33)
Caffeine reduces blood flow to the brain by as much as 27%. (34)
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Blood flow is the delivery system for getting nutrients of all kinds to your brain including oxygen, glucose, vitamins, and minerals.
Many people take brain supplements and nootropics like ginkgo, citicoline, curcumin, resveratrol, and vinpocetine to increase blood flow to the brain not realizing the caffeine they drink could be rendering them useless.
13. Women experience hormone-related sensitivity to caffeine
Caffeine’s effects vary depending on how quickly you process it.
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This means you’ll get double the boost and the side effects from any caffeine you consume.
Caffeine also increases symptoms of menopause including anxiety, insomnia, hot flashes, bone loss (by leaching calcium), heart palpitations, and mood swings. (37)
Likewise, caffeine can increase the anxiety, fatigue, and irritability experienced as part of PMS. (38)
14. Caffeine induces “panic attacks on demand” for scientific research
It’s notoriously difficult to study panic attacks since you can’t get study subjects to experience them on demand.
Or can you?
Caffeine so reliably induces panic attacks that it’s used for that purpose in studies.
By giving participants who had social anxiety disorder 480 mg of caffeine, 61% experienced panic attacks. (39)
Researchers have also used caffeine to induce auditory hallucinations (i.e., hearing things) in test subjects.
15. Caffeine withdrawal causes anxiety
If you have anxiety, caffeine gets you coming and going.
Not only does it make you feel anxious when you drink it, it also makes you anxious when you quit drinking it!
Caffeine withdrawal is a recognized mental disorder.
Withdrawal symptoms include anxiety as well as brain fog, depression, irritability, fatigue, insomnia, muscle aches, and nausea.
Fortunately, the worst of caffeine withdrawal usually lasts only a few days.
Caffeine and Anxiety: The Bottom Line
Caffeine is not the innocuous substance it seems to be.
The evidence is overwhelming that caffeine, a psychoactive drug, can exacerbate or cause anxiety.
Caffeine causes anxiety by many mechanisms — increasing stress hormones, reducing calming neurotransmitters, causing reactive hypoglycemia, depleting nutrients, and reducing blood flow to the brain.
If you’ve decided that eliminating caffeine would be a good idea, learn how to quit caffeine with minimal side effects in our article on caffeine addiction.