You read the same email three times and still can't take it in. You walk into the kitchen and forget why you came. Words sit on the tip of your tongue. Yes, anxiety and stress can make your thinking feel foggy. Brain fog can be one sign that worry, stress or low mood is taking up a lot of mental room. The good news is that this kind of fog often eases as the load gets lighter.
This post is general information, not medical advice or a diagnosis.
Can anxiety cause brain fog?
"Brain fog" is not a medical term. It is an everyday way to describe thinking that feels slow, cloudy or scattered. Many people notice it during anxious, stressful or low stretches of life.
Trouble focusing is a common part of anxiety. The National Institute of Mental Health lists having a hard time concentrating among the signs of generalized anxiety disorder (see Sources). The Centre for Addiction and Mental Health also names trouble concentrating as a common symptom (see Sources).
Brain fog can have many causes, so this post does not try to explain all of them. It focuses on the stress, anxiety and mood side, which is where counselling can help.
What anxiety brain fog can feel like
People describe brain fog in different ways. You might notice:
Reading a page and not remembering what it said
Losing your train of thought in the middle of a sentence
Forgetting small things, like why you opened an app or where you put your keys
Taking longer to make simple choices
Feeling like your mind is "full" or "buzzing" but not getting anywhere
Feeling mentally tired after a normal day
These moments can be scary, especially if you are already anxious. It's common to start worrying about the fog itself. That extra worry can make it harder to think, which can turn into a loop.
Why worry crowds out focus and memory
A helpful way to understand anxiety brain fog is to think about mental room.
Researchers have a model called attentional control theory. It suggests that anxiety pulls attention toward worries and possible threats, and makes it harder to keep attention on the task you chose (Eysenck and colleagues, 2007, see Sources). The same paper suggests that anxious people can often still do the task well, but it may take more effort. That fits what many people say: "I got it done, but it was exhausting."
Working memory is the part of your mind that holds information for a short time, like a phone number you are about to type. A large review of 177 samples found that higher anxiety was linked with poorer scores on working memory tasks (Moran, 2016, see Sources). This is a link across many studies. It does not mean anxiety damages your memory.
Put simply, worry takes up space. When part of your mind is busy scanning for problems, there is less room left for the email in front of you.
Brain fog and depression
Low mood can affect thinking too. People with depression often say their mind feels slow or heavy. Decisions can feel huge, and it can be hard to start or finish things.
A review of research found moderate differences in thinking skills, such as memory, attention and planning, in people with depression compared with people without it (Rock and colleagues, 2014, see Sources). Some of those differences in attention and planning were still there after mood had improved.
This does not mean anything is wrong with you as a person. It means that mood and thinking are connected, and both are worth care. Support for low mood can include support for the way it affects your focus.
Brain fog, stress and tiredness
Stress and tiredness often travel together. Long weeks, poor sleep, caring for others and constant decisions can leave very little in the tank.
When you are worn out, small choices can feel strangely hard. Our post on decision fatigue explains why making choice after choice can drain you.
Not all stress is harmful. Some stress helps you rise to a challenge. Our post on good stress vs bad stress explains the difference. Fog often shows up when stress stays high for a long time with little chance to recover.
Some people also notice that focus problems go back as far as childhood, long before any stressful season. That is worth a different conversation with a professional, and it is not something to diagnose from a blog post.
Small ways to clear the fog
You can't think your way out of fog by trying harder. But a few small changes can lower the load on your mind.
Do one thing at a time. Close extra tabs. Finish one small task before you start the next.
Write it down. Lists, sticky notes and reminders hold information so your mind does not have to.
Set a "worry time." Pick a short time each day to write your worries down. When a worry pops up at other times, jot it down and save it for later.
Get worries out of your head. A few minutes of writing can help. Our post on journaling for anxiety has simple ways to start.
Take short breaks. A few minutes away from a screen can help your attention reset.
Keep a steady rhythm. Regular sleep and wake times, meals and some movement can help your mind and body feel steadier.
Be kind to yourself. Fog is a sign of a full load, not a lack of effort. Harsh self-talk adds more worry.
Try one or two of these for a week rather than all at once. Small, steady steps are easier to keep.
When brain fog is a sign to reach out
It may be time to talk to someone if:
The fog lasts most days for weeks
It is affecting your work, school or relationships
You feel anxious, on edge or low most of the time
You have stopped enjoying things you used to enjoy
You are worried about yourself and don't know where to start
If you are thinking about suicide or hurting yourself, call or text 9-8-8 now. If you or someone else is in immediate danger, call 911.
How counselling can help
A foggy mind is often a tired, worried mind, and that can get easier. Counselling can help with the anxiety and mood side of brain fog.
A therapist can help you understand what is filling up your mental space. Cognitive behavioural therapy (CBT) for anxiety can help you notice worry loops, test anxious thoughts and build calmer habits. Support for low mood can help you slowly get back to the things that matter to you. If you want a clearer picture of what is going on, psychologists on our team can do assessments.
We offer counselling at our Kitchener-Waterloo, Cambridge and Ottawa offices and online across Ontario.
Common questions about brain fog and anxiety
Can anxiety cause brain fog? Anxiety can make it harder to focus and remember things, and many people describe this as brain fog. It can be one sign that worry is taking up a lot of mental room.
Is anxiety brain fog permanent? For many people it eases as stress and worry ease. Research links anxiety with poorer working memory scores, but that is not the same as lasting damage.
Can depression make it hard to think? Yes. Low mood can make thinking feel slow, and it can affect attention and memory.
How do I clear brain fog from stress? Lower the load where you can. Try one task at a time, write things down, take short breaks and keep a steady daily rhythm.
Cost, billing and your first step
Sessions with our therapists range from $130 to $200, depending on the clinician.
We accept Health Spending Accounts (HSAs).
We can direct bill many insurers. Coverage depends on your plan, so check with your insurer before you start.
Book a free 15-minute consultation with our admin team. A foggy mind is often a tired, worried mind, and that can get easier. We can help you find a place to start.
If you're in crisis: if you or someone you love is in immediate danger, call 911. If you're thinking about suicide, call or text 9-8-8 any time, day or night.
Last reviewed: October 2026
Sources
Eysenck MW, Derakshan N, Santos R, Calvo MG. "Anxiety and cognitive performance: attentional control theory." Emotion. 2007;7(2):336-353. https://pubmed.ncbi.nlm.nih.gov/17516812/
Moran TP. "Anxiety and working memory capacity: A meta-analysis and narrative review." Psychol Bull. 2016;142(8):831-864. https://pubmed.ncbi.nlm.nih.gov/26963369/
Rock PL, Roiser JP, Riedel WJ, Blackwell AD. "Cognitive impairment in depression: a systematic review and meta-analysis." Psychol Med. 2014;44(10):2029-2040. https://pubmed.ncbi.nlm.nih.gov/24168753/
National Institute of Mental Health. "Generalized Anxiety Disorder: What You Need to Know." https://www.nimh.nih.gov/health/publications/generalized-anxiety-disorder-gad
Centre for Addiction and Mental Health. "Anxiety disorders." https://www.camh.ca/en/health-info/mental-illness-and-addiction-index/anxiety-disorders