Does anxiety cause brain fog? Why your mind feels cloudy, and what helps

You read the same email three times and still can’t take it in. You walk into a room and forget why. Words slip away mid-sentence, and your head feels like it’s full of cotton wool.

“Brain fog” isn’t a medical diagnosis, but it’s a very real experience, and anxiety is one of the most common reasons for it. Here’s why it happens, what else can cause it, and what helps.

What brain fog feels like

• finding it hard to concentrate or follow conversations
• forgetting things, like names, appointments or why you came into a room
• slow or muddled thinking
• struggling to find the right word
• feeling mentally tired, even after rest
• finding decisions harder than usual
• feeling detached or “not quite here”

Why anxiety causes brain fog

Worry uses up your mental workspace

Your brain has a limited “workspace” for holding and juggling information, called working memory. When you’re anxious, worries take up a lot of that space, leaving less for the task in front of you. A large review, covering more than 22,000 people, found that people with higher anxiety did consistently worse on working memory tasks.

Your attention is pulled towards threats

Anxiety tunes your brain to scan for danger. That’s useful in a real emergency, but in everyday life it means your attention keeps getting dragged back to worries and body sensations, instead of what you’re trying to do.

Poor sleep

Anxiety often disrupts sleep, and even a few short nights make concentration and memory noticeably worse.

Exhaustion after adrenaline

Living with high anxiety, or having panic attacks, uses a lot of energy. Afterwards, many people feel wiped out and foggy. Our post on the panic attack hangover explains why.

Overbreathing

Breathing fast or shallowly when you’re anxious can lower the carbon dioxide in your blood, which can make you feel light-headed, spacey and unreal.

Feeling unreal

Some people with anxiety feel detached from themselves or the world, as if they’re watching through glass. This is called depersonalization or derealization, and it can feel a lot like fog. Our post on what derealization feels like explains more.

Difficulty concentrating is one of the main symptoms of generalised anxiety disorder, so if brain fog comes with constant worry, anxiety may well be the cause.

Other causes of brain fog

Brain fog has many causes, and more than one can be at play. It’s worth thinking about:

• Sleep problems, including sleep apnea, where your breathing stops and starts at night
• Depression, which often slows thinking and memory
• ADHD, which can cause lifelong difficulty with focus and organisation, and often overlaps with anxiety
• An underactive thyroid, which can cause tiredness, slowed thinking and weight gain
• Low iron or vitamin B12, which can cause tiredness and poor concentration
• Medicines, including some antihistamines, sleeping tablets, benzodiazepines, strong painkillers and some antidepressants
• Alcohol and cannabis, including the day after
• Menopause and perimenopause, which commonly cause brain fog and memory problems
• Long COVID, where brain fog can last for months after the infection
• Pregnancy and the months after having a baby
• Dehydration and not eating enough

A doctor can check for many of these with a conversation and simple blood tests.

When to get help urgently

Call 911 (or your local emergency number) straight away if you or someone else has:

• sudden confusion, or trouble understanding speech
• slurred or garbled speech
• a face that droops on one side
• weakness or numbness in an arm or leg, especially on one side
• sudden trouble seeing, walking or keeping balance
• a sudden, severe headache

These can be signs of a stroke, and every minute counts.

See a doctor soon if:

• brain fog has come on over weeks and is getting worse
• memory problems are affecting your daily life, or other people have noticed them
• it started after a head injury
• it comes with other new symptoms, like weight changes, feeling very cold or very hot, or unusual tiredness

What helps clear the fog

• Calm your body first. Slow breathing, in for 4 and out for 6, helps settle the worry that’s hogging your mental space.
• Get the worries out of your head. Write them down. A “brain dump” frees up working memory.
• Do one thing at a time. Multitasking is especially hard when you’re anxious. Close extra tabs, silence notifications and focus on the next small step.
• Write things down. Lists, calendar reminders and notes do the remembering for you, so your brain doesn’t have to.
• Protect your sleep. Regular sleep and wake times help more than lie-ins.
• Move. A short walk, especially outside, can sharpen your thinking for a while afterwards.
• Eat and drink regularly. Your brain needs fuel and water.
• Go easy on caffeine and alcohol. Too much caffeine adds jitters, and alcohol disrupts sleep.
• Treat the anxiety. As anxiety eases, the fog usually lifts. Cognitive behavioural therapy (CBT) and, for some people, medicine can help.

Frequently asked questions

How long does anxiety brain fog last?

It usually comes and goes with your anxiety. After a panic attack or a very stressful day, it might last a few hours or until you’ve slept. With ongoing anxiety, it can linger for weeks, and it often lifts as the anxiety is treated.

Can anxiety make you forgetful?

Yes. When worries are taking up your working memory, it’s harder to take in new information, so things don’t get stored properly in the first place. It’s not a sign that your memory is damaged.

Is brain fog a sign of something serious?

Usually, brain fog is caused by common things like anxiety, poor sleep, stress or a medicine. But sudden confusion is an emergency, and fog that keeps getting worse over weeks should be checked by a doctor.

Can anxiety make you feel spaced out?

Yes. Overbreathing, exhaustion and feelings of unreality (derealization) can all make you feel spaced out or not quite present. Slow breathing and grounding through your senses help.

How Breatheasy can help

Breatheasy can help settle the anxiety that clouds your thinking. A one-minute breathing exercise pulses your phone as you breathe in, so you can close your eyes and let your mind rest. Ten-second check-ins and a journal help you see whether foggy days follow poor sleep, stressful weeks or particular situations, which is useful to share with a doctor. Breatheasy is coming soon to iPhone and Android.

Sources

• Anxiety and working memory capacity: a meta-analysis and narrative review, Moran, Psychological Bulletin, 2016
• Generalised anxiety disorder in adults, NHS
• Symptoms of a stroke, NHS
• Underactive thyroid, NHS
• Vitamin B12 or folate deficiency anaemia, NHS
• Menopause symptoms, NHS
• Long-term effects of COVID-19 (long COVID), NHS
• Sleep apnoea, NHS