Caffeine, alcohol and anxiety: what a GP wants you to know

In clinic, when someone tells me their anxiety has crept up, two of my first questions are unglamorous: how much caffeine are you having, and how much are you drinking? Not because either one causes anxiety on its own, but because both can quietly turn the volume up, and both are things you can actually change this week. No scare tactics here, just what the evidence says and what I tend to suggest.

The short version

• Caffeine is linked with a higher risk of anxiety symptoms, and the effect gets much stronger above roughly 400 mg a day, which is about four cups of filter coffee.
• Alcohol feels calming for an hour or two, but regular heavy drinking is linked with anxiety and depression, and the rebound often shows up the next morning.
• You do not need to quit either. Sensible caps, earlier cut-off times and a few drink-free days are where I would start.
• If you cannot cut down without feeling shaky, sweaty or panicky, that needs a doctor, not willpower.

Caffeine: the anxious brain's frenemy

Caffeine is a stimulant. We forget this because it arrives in a friendly mug, but it is the same substance whether it comes from an espresso, a builder's tea or a bright cold can.

The research is fairly consistent. A 2024 meta-analysis in Frontiers in Psychology pooled trials in healthy people, without any anxiety disorder, and found that caffeine intake increased anxiety measures overall. The interesting part is the dose. Below about 400 mg a day the effect was moderate. At or above 400 mg it was large, and the authors' plain recommendation was that healthy adults stay under 400 mg a day. That matches the position of the European Food Safety Authority, whose review concluded that up to 400 mg a day, and up to 200 mg in one go, raises no safety concerns for healthy adults. In pregnancy the advised ceiling halves to 200 mg a day.

Nobody thinks of their fourth coffee as a drug dose. Your nervous system counts it as one anyway.

How much is actually in your cup

Using EFSA's typical figures: a 200 ml cup of filter coffee has about 90 mg, an espresso about 80 mg, a 250 ml energy drink about 80 mg, a cup of tea about 50 mg, and a can of cola about 40 mg. So "I only have three coffees" can easily mean 300 mg before lunch, and a fourth pushes you into the zone where the anxiety effect gets steep.

Timing matters too. EFSA notes that doses as small as 100 mg can affect sleep when taken close to bedtime, and poor sleep and anxiety feed each other, something we covered in the 3am cycle. If your heart races and your chest feels tight after coffee, that is a real physiological response, not imagination; anxiety and stimulants share a lot of physical wiring.

How to actually count it

One ordinary day is enough. Note every caffeinated drink and its real serving size, then price each one using the figures above. Three honesty checks. A home mug is often 300 ml rather than 200, so a big filter coffee is nearer 135 mg. A large high-street coffee is usually two or three shots, and the big chains publish caffeine figures on their websites. And cans do the maths for you: any drink over 150 mg of caffeine per litre must be labelled "high caffeine content" with the amount in mg per 100 ml. Include tea, cola, chocolate and pre-workout supplements. The total will be rough, but easily good enough to answer the question that matters: are you over 400 mg?

My practical suggestions: keep it under 400 mg, move your last caffeine to before 2pm, and if you suspect caffeine is winding you up, halve it for two weeks and see. Cut down gradually rather than stopping dead, because abrupt withdrawal can give you headaches and a rough few days.

Alcohol: calm now, interest charged later

Alcohol is the opposite trap. Where caffeine mimics anxiety, alcohol temporarily muffles it, which is exactly why anxious people are drawn to it. A drink works, briefly. The problem is what happens on repeat.

The NHS is clear that longer-term risks of drinking too much include mental health conditions such as anxiety and depression, alongside the better-known physical harms, and that there is strong evidence linking alcohol misuse with self-harm. In other words, the nightly "medicine" is also a maintenance dose for the problem it treats.

Many of my patients describe the morning-after version: waking early with a thumping heart and a sense of dread out of proportion to anything real. As the sedative effect wears off, the nervous system swings back the other way. In people who have become dependent, anxiety, poor sleep, sweating and a racing heartbeat are recognised withdrawal symptoms, which is why the pattern of drinking to calm down, then waking anxious, then drinking again, deserves attention early.

What sensible looks like

UK guidance is the same for men and women: no more than 14 units a week on a regular basis, spread over three or more days, with some drink-free days if you want to cut down. Fourteen units is roughly six pints of average-strength beer or ten small glasses of wine. The NHS calls staying under this "low risk" rather than "safe", because there is no risk-free level, but as a GP I care most about the pattern: daily drinking to manage feelings is a louder alarm bell than the occasional big Saturday.

One honest test I offer patients: two completely alcohol-free weeks. If your anxiety improves, you have learned something valuable. If you find you cannot manage two weeks, you have learned something even more valuable, and it is worth a conversation with your GP.

Where to start this week

Pick one lever, not five. Swap your afternoon coffee for a decaf, or protect three drink-free evenings. Small, boring, repeatable changes beat dramatic overhauls. Tracking your mood alongside the change for a couple of weeks in an app like brightloaf makes the pattern hard to miss.

One important caution: if you drink heavily every day, do not stop suddenly. Abrupt withdrawal from alcohol dependence can be dangerous, so get medical help to come off safely. And this article is general information, not a substitute for personal medical advice; if drink or anxiety is getting on top of you, your GP or an NHS alcohol support service is the right next step. If you are in crisis, call 999 or go to A&E; brightloaf is not a crisis service.