15 Links Between Caffeine and Anxiety

Edited and medically reviewed by Patrick Alban, DC | Written by Deane Alban

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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.

If you have an anxiety disorder, and you’re concerned that caffeine is making it worse, your suspicions may be right.

Caffeine is a central nervous system stimulant that can significantly contribute to anxiety disorders. (1)

There’s evidence that quitting caffeine can be even more beneficial for anxiety than taking prescription anti-anxiety drugs!

Here are 15 ways that caffeine is linked to anxiety … and what you can do about it.

1. Caffeine Increases Stress Hormones

Most people who deal with anxiety would agree that they have too much stress in their lives — and caffeine adds to the burden.

Caffeine affects the body much like stress by increasing heart rate, blood pressure, and levels of stress hormones.

" Some psychiatrists recommend that routine psychiatric assessments should include examining caffeine consumption since removing caffeine can be more beneficial than prescribing anti-anxiety drugs.

Caffeine consumption can more than double the blood levels of the stress hormones cortisol and epinephrine. (2, 3)

2. Caffeine Affects Neurotransmitter Balance

Caffeine achieves many of its effects by blocking the activity of adenosine, a neurotransmitter that makes you feel sleepy and tired.

By increasing the brain chemicals dopamine and acetylcholine, caffeine imparts feelings and results that we desire, such as increased motivation, mental function, and productivity. (4, 5)

But for those with anxiety, there is a downside.

Caffeine also inhibits the calming neurotransmitter GABA (gamma-aminobutyric acid). (6)

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GABA slows brain activity when needed and has been called “nature’s Valium.”

It’s essential for feeling happy and relaxed, so it’s not surprising that a low GABA level is associated with anxiety and panic attacks.

Serotonin is the neurotransmitter most closely tied to happiness.

But there’s evidence that caffeine, which can cross the blood-brain barrier, decreases levels of serotonin in the brain. (7, 8)

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 psychiatric disorder. (9)

If anxious thoughts make you restless at night, caffeine can compound the problem.

Caffeine particularly decreases sleep stages 3 and 4 during which deep, restorative sleep takes place. (10)

Getting adequate high-quality sleep is one of the most important things you can do for brain health and mental well-being.

It’s during sleep that your brain washes away toxins and metabolic debris, repairs itself, consolidates memories, and creates new brain cells. (111213)

Caffeine consumed even six hours before bedtime can significantly disrupt sleep, so you may find that you need to stop caffeine ingestion earlier than you thought. (14)

4. You May Have Caffeine Sensitivity

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.

Scientists from Harvard School of Public Health have found several genes that directly influence how your body metabolizes caffeine. (15)

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You may be sensitive to caffeine because you take longer than average to metabolize it.

The average half-life of caffeine is 5-6 hours, but everyone is different and the time it can take to eliminate caffeine varies widely.

It can take as little as two to as many as ten hours after ingestion to metabolize half of it. (16)

And there are other reasons you may be sensitive to caffeine.

Caffeine sensitivity increases with age, so you might not be able to drink caffeine like you used to. (17)

Men metabolize caffeine more slowly than most women, the exceptions being women who are pregnant or taking birth control pills. (18, 19)

Caffeine sensitivity can be caused by an allergic reaction to caffeine, although true caffeine allergy is rare. (20)

More common is an allergy to mycotoxins, toxins produced by fungi and mold, that are found in coffee. (21)

You may be taking medications that increase the side effects of caffeine.

Drinking alcoholic beverages slows down caffeine breakdown.

So do some healthy foods such as broccoli and some herbal teas. (22)

Impaired ability to process caffeine is not unusual in people with liver disease, especially cirrhosis. (23)

5. Caffeine May Aggravate Hypoglycemia

Hypoglycemia occurs when your blood sugar drops too low.

A low blood sugar attack can leave you feeling jittery, sweating, irritable, and confused, with a pounding heart — a lot like an anxiety attack.

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Caffeine stimulates the release of the stress hormones cortisol, epinephrine, and norepinephrine, causing blood sugar levels to drop. (24)

If you suspect that your low blood sugar is exacerbated by caffeine, try going without it and notice if you experience any improvement.

6. Medications Plus Caffeine Can Increase Anxiety

Caffeine is so much a part of our culture that it’s easy to forget that it’s a psychoactive drug and, consequently, doesn’t always mix well with other drugs.

Drugs.com currently lists more than 50 medications that should not be taken with caffeine.

Sometimes caffeine enhances the effects of some drugs — it’s often added to over-the-counter painkillers to make them work better.

But this same property also increases the number of side effects as is the case with asthma medications, antidepressants, and some antibiotics. (25, 26)

Sometimes caffeine undermines the effectiveness of medications.

Anti-anxiety medications, sleeping pills, and lithium for bipolar disorder fall into this category.

Pharmacist Suzy Cohen, RPh, 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.

She reports that 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.

When taken together, they can cause anxiety as well as dangerous heart palpitations, 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, contain caffeine naturally.

But the caffeine found in sodas, energy drinks, energy gel packs, and caffeine pills and powders is rarely extracted from tea leaves or coffee grounds — that would be prohibitively expensive.

The demand for added caffeine has far outstripped natural caffeine production since World War II.

Added caffeine is synthetically manufactured in pharmaceutical plants from chemical precursors like urea and chloroacetic acid.

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It is usually made in China or sometimes in 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 caffeine factory 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.

He reveals that if you drink soda or energy drinks, you’ve almost certainly consumed caffeine produced there.

Lastly, don’t be impressed if you see the words “naturally caffeinated” on a product label.

It’s not unusual for manufacturers to ignore labeling requirements and use the synthetic version anyway. (27)

Natural and synthetic caffeine are technically identical, yet can be told apart by carbon dating. (28)

Synthetic caffeine registers as “older” since it’s made from fossil fuels.

Oddly, synthetic caffeine can exhibit another telltale sign — sometimes it glows! (29)

8. Too Much Caffeine Is Linked to Psychiatric Disorders

It’s been recognized for decades that the symptoms of too much caffeine are very similar to those of many psychiatric disorders.

Enough 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 prescribing anti-anxiety drugs.

Caffeine use has been linked to mental disorders of all kinds including anxiety, panic, depression, as well as sleep and eating disorders.

Taking schizophrenic patients off caffeine has improved their anxiety, irritability, and hostility. (30)

Some experts are so convinced that caffeine is problematic, they’ve recommended that only decaffeinated beverages be available in psychiatric wards. (31, 32)

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9. Caffeine Causes at Least Four Recognized Mental Disorders

The Diagnostic and Statistical Manual of Mental Disorders (DSM) is the American Psychiatric Association’s standard guide of mental disorders.

The most recent edition is the fifth version known as the DSM-5.

The DSM-5 now lists four caffeine-related disorders: (33)

  • caffeine intoxication
  • caffeine-induced anxiety disorder
  • caffeine-induced sleep disorder
  • caffeine withdrawal

The World Health Organization and many health care professionals recognize caffeine addiction as a clinical disorder.

For now, the preferred term is caffeine use disorder. (34)

It’s been included as a condition for further study in the DSM-5.

10. It’s Easier Than Ever to Overdo Caffeine Consumption

There are more sources of 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. (35)

Caffeine is commonly added to so-called brain supplements, often as part of a proprietary blend which means that the label doesn’t tell you how much caffeine the supplement contains.

The amount of caffeine in energy drinks can be deceiving since some of the serving sizes of these drinks are so small.

5-Hour Energy Shot contains a jaw-dropping 100 mg of caffeine per ounce.

Another problem is that labels aren’t always accurate.

Sunkist orange soda lists 41 mg of caffeine on its label, but in fact, was found to have almost six times as much caffeine at 240 mg per bottle. (36)

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Caffeine’s effects are consistently underestimated.

According to the book Caffeinated, here’s what escalating amounts of caffeine can do to you:

  • 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

It’s thought to be 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.

Sadly, there have been numerous deaths caused by caffeine powder overdose. (3738)

11. Caffeine Robs You of Essential Brain Nutrients

Caffeine causes nutrients to be excreted from your body, some of which are particularly important for your brain health and mood.

One of the nutrients that gets depleted is magnesium, a mineral that has profound effects on your mental wellness. (39)

Magnesium plays a critical role in a number of brain-related disorders including: (4041, 4243)

  • addictions
  • Alzheimer’s disease
  • anxiety
  • attention disorders
  • bipolar disorder
  • depression
  • schizophrenia

Caffeine also robs you of the B complex vitamins which act as “anti-stress vitamins.”

Anxiety is a common sign of B vitamin deficiency. (44)

Taking extra B vitamins can address imbalances of the brain chemicals GABA, serotonin, dopamine, and epinephrine that contribute to anxiety. (45)

12. Caffeine Restricts Blood Flow to the Brain

When you are anxious, blood flow to the brain is already reduced and caffeine can reduce it further. (46)

Caffeine restricts blood flow to the brain by as much as 27%. (47)

Blood flow is the delivery system for getting nutrients of all kinds to your brain including oxygen, water, glucose, vitamins, and minerals.

An interesting aside is that many people take brain supplements and nootropics like ginkgo, citicoline, curcumin, and vinpocetine which work, in part, by increasing blood flow to the brain — not realizing that the caffeine they drink essentially neutralizes this benefit!

13. Women Experience Hormone-Related Sensitivity to Caffeine

Caffeine’s effects vary depending on how quickly you process it.

If you are pregnant or taking birth control pills, it can take longer to process caffeine than usual, up to twice the usual half-life of four to five hours. (48, 49)

This means you’ll get double the boost and 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.

Likewise, caffeine can also worsen the anxiety, fatigue, and irritability experienced by women with premenstrual syndrome (PMS).

14. Caffeine Induces “Panic Attacks on Demand” for Scientific Research

It’s notoriously difficult to study panic attacks since study subjects don’t experience them on demand.

Or can they?

Caffeine so reliably induces panic attacks that it’s used for that purpose in studies.

By giving participants with social anxiety disorder 480 mg of caffeine, 61% of them experienced caffeine-induced panic attacks. (50)

Researchers have also used caffeine to induce auditory hallucinations (i.e., hearing non-existent sounds) in test subjects. (51)

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. (52)

Withdrawal symptoms include anxiety as well as brain fog, depression, irritability, fatigue, insomnia, muscle aches, and nausea.

This may make you reluctant to try quitting, but it’s still worth it since the worst of caffeine withdrawal usually lasts only a few days.

The Worst and Best Caffeinated Drinks If You Have Anxiety

Not all sources of caffeine are equally beneficial or detrimental.

Soft drinks contain synthetic caffeine, loads of sugar, and have no nutritive value.

Energy drinks are no better even though they may contain some added herbs or vitamins.

The International Society of Sports Nutrition has concluded that any performance enhancement from energy drinks comes from caffeine and sugar, NOT from these added nutrients. (53)

Traditional caffeinated drinks like coffee, tea, and yerba mate contain antioxidants, vitamins, minerals, amino acids, and phytonutrients that offer major health benefits and actually build a better, healthier brain.

If you’d like to continue to drink some caffeine to stay alert and productive, there’s no better drink than green tea.

Green tea will help you stay simultaneously calm and focused due to two unique compounds, EGCG and l-theanine.

EGCG (epigallocatechin gallate) is a potent antioxidant that can improve your mood and make you more resilient to stress by moderating brainwave activity and increasing the calming neurotransmitter GABA. (54, 55, 56)

One study found EGCG to be as effective at relieving anxiety as the anti-anxiety medication benzodiazepine. (57)

L-theanine is a relaxing amino acid that causes an increase in alpha brainwave activity, putting you in a state similar to that experienced during meditation. (58)

The caffeine, EGCG, and theanine in green tea work together to induce a desirable state of calm alertness. (59)

Caffeine and Anxiety: Take the Next Step

For some, caffeine is not the innocuous substance it might seem to be.

The evidence is overwhelming that this psychoactive drug can exacerbate or cause anxiety.

It’s been linked to a handful of recognized psychiatric disorders.

Caffeine causes anxiety by many mechanisms — increasing stress hormones, reducing calming neurotransmitters, depleting nutrients, and reducing blood flow to the brain.

If you’re going to drink any caffeinated drink, a healthier choice is green tea which contains relaxing compounds.