Guide · Research

Caffeine and Panic: What the Research Says

By Vernon B · Reviewed and edited by Vernon B · Updated Oct 20, 2026

By Vernon B · Help My Attacks · Peer support, not medical advice

Many of us know this moment. You finish a big coffee or an energy drink, and an hour later your heart is thumping, your hands are shaky, and a familiar dread starts to rise. Is this panic? The coffee? Both? It can make your morning cup feel like a small gamble.

So we went looking for what the research actually shows. We're a peer-support community, not doctors, so every number below links to its source. Please read this as background for your own noticing and for a conversation with a professional, not as a rule or a treatment plan.

Why caffeine and panic can feel so alike

Caffeine and panic share a lot of the same body sensations. The U.S. Food and Drug Administration (FDA) lists signs of too much caffeine such as a faster heart rate, palpitations, jitters, anxiety, nausea, headache, and trouble sleeping. The National Institute of Mental Health (NIMH) lists panic symptoms like a pounding or racing heart, trembling, sweating, and nausea. The overlap is striking.

That matters because of how panic works. NIMH describes panic attacks as possible "false alarms": someone feels their heart pounding, assumes something is badly wrong, and that fear feeds a vicious cycle. If caffeine sped your heart up, it can hand your alarm system the first spark.

Mayo Clinic lists smoking or excessive caffeine intake among factors that may raise the risk of panic attacks, and the NHS suggests avoiding caffeine, alcohol, and sugary food and drinks because they can all make attacks worse. But that doesn't tell us how much, or for whom. That's where the studies come in.

What caffeine challenge studies found

In caffeine challenge studies, volunteers get either caffeine or a look-alike placebo without knowing which, and researchers watch what happens. Many compared people with panic disorder to people without it.

The big picture: a 2022 meta-analysis

In 2022, Lisa Klevebrant and Andreas Frick pooled these studies in a meta-analysis in General Hospital Psychiatry. Out of 1,893 articles, ten met their standards: blinded, placebo-controlled studies of a single caffeine challenge in adults with panic disorder. They found:

• Across nine studies that tracked panic attacks, there were 237 people with panic disorder. 51.1% had a panic attack after caffeine, and none had one after placebo.
• Six of those studies also included people without panic disorder. After caffeine, 53.9% of the people with panic disorder had a panic attack, compared with 1.7% of the healthy comparison group.
• Caffeine raised anxiety in both groups, but people with panic disorder showed more sensitivity to its anxiety-raising effects.

The doses really matter here. The studies used 400 to 750 mg of caffeine at once, most often 480 mg, which the authors describe as roughly five cups of coffee. They noted that little is known about smaller doses.

An earlier review pointed the same way

A 2011 systematic review by Vilarim, Rocha Araujo, and Nardi looked at eight randomized, double-blind studies. All eight showed a positive link between caffeine and anxiety effects and/or panic.

What about a more everyday amount?

A Swedish team (including both meta-analysis authors) then tested something closer to real life. In a 2025 trial, 29 people with panic disorder and 53 without it, all light caffeine users, got either 150 mg of caffeine or a placebo on different days. Contrary to what the researchers expected, 150 mg did not raise subjective anxiety in either group, and only one panic attack was recorded in the whole study.

Caffeine still raised a physical arousal measure and increased what the researchers call costly avoidance behavior in both groups. The authors suggested caffeine advice for people with panic disorder be based on higher doses and, ideally, individual assessment. In other words: dose matters, and so do you.

Why one person's coffee is another person's racing heart

If a friend can drink espresso at 9 p.m. while half a cup leaves you wired, you're not imagining it. The FDA notes wide variation in how sensitive people are to caffeine and how fast they clear it, with body weight, medications, and health conditions playing a part. Research adds a few more pieces:

• Genes. In a 2003 study of 94 healthy light caffeine users, people with one version of an adenosine receptor gene (ADORA2A) reported bigger jumps in anxiety after 150 mg, a variation the authors noted had also been linked to panic disorder. A 2008 study of 102 people found that 50 mg didn't raise anxiety, while 450 mg raised it in most participants.
• Habit. Mayo Clinic notes that if you don't drink caffeine daily, you might react more to it.
• How scary the sensations feel. Anxiety sensitivity means fear of your body's own arousal signals. In a 1996 study of 72 people without panic disorder, those high in it had a stronger emotional reaction to 450 mg of caffeine, especially when given no sense of control.
• Expectation. When a German study gave caffeine in coffee (expected) or hidden in a bitter lemon soda, body arousal and symptom reports were greater when it came in coffee.

We find those last two quietly hopeful. The meaning we give a sensation is part of the picture, and that's something people can work on, often with a therapist. More on the "false alarm" loop in what the research says about panic.

Where caffeine hides

Coffee isn't the only source. The FDA's typical amounts for a 12-ounce drink:

• Regular brewed coffee: about 113 to 247 mg
• Energy drinks: about 41 to 246 mg
• Caffeinated soft drinks: about 23 to 83 mg
• Black tea: about 71 mg
• Green tea: about 37 mg

Tea and chocolate are well known, but the FDA also lists energy or protein bars, ice cream, chewing gum, dietary supplements, and over-the-counter medicines, and Mayo Clinic notes some nonprescription pain relievers contain caffeine. Decaf isn't zero either: typically 2 to 15 mg in an 8-ounce cup.

For general context only, not a target: the FDA says 400 mg a day, about two to three 12-ounce cups of coffee, is an amount not generally associated with negative effects for most healthy adults. The lab doses that triggered panic in about half of participants were in that range or higher, taken at once. "Generally fine for most adults" and "fine for a body prone to panic" aren't always the same thing.

Cutting back can feel rough too

If your body is used to daily caffeine, going without suddenly can feel lousy. A review by Juliano and Griffiths of 66 studies confirmed withdrawal symptoms including headache, fatigue, low mood, trouble concentrating, irritability, and fogginess. In experimental studies, half of people got headaches and 13% had symptoms that caused real distress or got in the way of daily life. Symptoms usually began 12 to 24 hours after the last caffeine, peaked at 20 to 51 hours, and lasted 2 to 9 days, even for people used to as little as 100 mg a day.

A pounding head and feeling "off" are exactly the kind of sensations an anxious brain likes to grab. The FDA says withdrawal isn't considered dangerous but can be unpleasant and that cutting back is best done gradually; Mayo Clinic also suggests going little by little. If you're thinking about changes, a quick chat with your doctor or pharmacist is a kind thing to do for yourself, especially if you take medication, have a health condition, or are pregnant.

The honest limits of this research

Here's what these studies can't tell us:

• Small studies. 237 people across nine studies is about 26 per study, small by research standards.
• Lab doses, not daily life. Most used one large dose at once. The narrow range ruled out a dose-response analysis, and little is known about smaller doses.
• Missing pieces. Only two of the ten studies reported anxiety data after placebo.
• Quality concerns. The 2011 review found none of its studies controlled for confounding factors, and dropout ranged from 14.3% to 73.1%.
• Specific groups. The low-dose trial and gene studies mostly involved light caffeine users. Daily drinkers may respond differently.

The fair summary: large single doses brought on panic in about half of people with panic disorder in the lab. Everyday amounts are much less studied, and the one recent modest-dose trial didn't find the same effect. Your own experience still counts.

A gentle way to notice your own pattern

Since research can't tell you exactly how your body responds, some of us find it helpful to get curious instead of afraid. No right outcome, no promises. Just noticing.

• Jot it down for a couple of weeks: what had caffeine, roughly when, how you slept, and how you felt over the next few hours. Our easy journaling ideas can help.
• Look for patterns, not proof. Do shaky afternoons follow the second energy drink? Rough nights follow late coffee? See panic attacks at night for more on sleep.
• Count hidden sources on pain reliever, supplement, and snack labels.
• Try naming it. "This might be the caffeine. My body is buzzing, and buzzing isn't danger." It won't shrink every wave, but it can take some fuel from the fear loop.
• Bring your notes to a professional. A pattern on paper is easier to talk through than a vague hunch.

And go easy on yourself. Caffeine is woven into comforting routines: the morning ritual, the coffee date with a friend. Noticing it isn't about guilt. It's about knowing your body a little better. For the bigger picture, see our guide to panic attacks and panic disorder.

When to get help

Caffeine is rarely the whole story. Please talk with a doctor or mental health professional if:

• You've had a first panic attack or new symptoms. Mayo Clinic notes panic can resemble other serious health problems, such as a heart attack, so get checked if you aren't sure.
• You have chest pain, fainting, or serious trouble breathing. That's a medical question first.
• Your heart races or skips often, with or without caffeine.
• Worry or avoidance is shrinking your life. NIMH says when anxiety starts to cause problems in everyday life, it's time to seek professional help.
• You're thinking about changing your caffeine habits and take medication or have a health condition.

A primary care provider is a good place to start, and talking therapies like CBT have strong research behind them.

If you ever feel unsafe or have thoughts of suicide, please reach out right away. In the US, you can call or text 988 to reach the Suicide & Crisis Lifeline. In a life-threatening emergency, call 911.

You noticed a pattern and went looking for answers. That's a caring thing to do for yourself. Whatever's in your mug tomorrow, you're not alone in figuring this out.

References

1. Klevebrant L, Frick A. Effects of caffeine on anxiety and panic attacks in patients with panic disorder: a systematic review and meta-analysis. General Hospital Psychiatry. 2022;74:22–31. doi:10.1016/j.genhosppsych.2021.11.005
2. Vilarim MM, Rocha Araujo DM, Nardi AE. Caffeine challenge test and panic disorder: a systematic literature review. Expert Review of Neurotherapeutics. 2011;11(8):1185–1195. doi:10.1586/ern.11.83
3. Hoppe JM, Björkstrand J, Vegelius J, Klevebrant L, Gingnell M, Frick A. Acute effects of 150 mg caffeine on subjective, physiological, and behavioral components of anxiety in panic disorder and healthy controls: a randomized placebo-controlled crossover trial. Journal of Psychopharmacology. 2025;39(8):836–846. doi:10.1177/02698811251344692
4. Alsene K, Deckert J, Sand P, de Wit H. Association between A2a receptor gene polymorphisms and caffeine-induced anxiety. Neuropsychopharmacology. 2003;28(9):1694–1702.
5. Childs E, Hohoff C, Deckert J, Xu K, Badner J, de Wit H. Association between ADORA2A and DRD2 polymorphisms and caffeine-induced anxiety. Neuropsychopharmacology. 2008;33(12):2791–2800.
6. Telch MJ, Silverman A, Schmidt NB. Effects of anxiety sensitivity and perceived control on emotional responding to caffeine challenge. Journal of Anxiety Disorders. 1996;10(1):21–35.
7. Pané-Farré CA, Alius MG, Modeß C, Methling K, Blumenthal T, Hamm AO. Anxiety sensitivity and expectation of arousal differentially affect the respiratory response to caffeine. Psychopharmacology. 2015;232(11):1931–1939.
8. Juliano LM, Griffiths RR. A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharmacology. 2004;176(1):1–29.
9. U.S. Food and Drug Administration. Spilling the Beans: How Much Caffeine is Too Much? Content current as of Aug 28, 2024. Accessed Oct 20, 2026.
10. Mayo Clinic Staff. Caffeine: How much is too much? Feb 21, 2025. Accessed Oct 20, 2026.
11. Mayo Clinic Staff. Panic attacks and panic disorder: Symptoms and causes. Accessed Oct 20, 2026.
12. National Institute of Mental Health. Panic Disorder: What You Need to Know. Accessed Oct 20, 2026.
13. NHS. Panic disorder. Page last reviewed Aug 22, 2023. Accessed Oct 20, 2026.