What Is Brain Fog? Symptoms, Causes and Treatments

We’ve all used the term “brain fog” from time to time to describe a feeling of mental fuzziness or the sense that our brain isn’t functioning as it normally does. In fact, the words “brain fog” have been used for more than a century, but we are hearing about it much more often since the COVID-19 pandemic. That’s because brain fog and mental health problems affect more than one in five people who have or had long COVID, according to a 2024 analysis of studies on long COVID by researchers at University of York, UK, and other institutions.

Brain fog affects both young and older people and both men and women. Typical brain fog symptoms include problems with cognition, memory and mental focus. While most of the time, it clears up quickly—even within a matter of days—in other cases and depending on the cause, it can persist for months or even years.

Unfortunately, there is no medical test to identify brain fog, nor is there any specific drug or intervention to help clear it. But brain health experts have identified several strategies to help you cope with it, says brain-health expert Jessica Fredericksen, MSW, CADDCT, CMDCP.

Important: if you’ve been forgetting things, repeating yourself, having trouble completing tasks, missing appointments, experiencing problems with concentration, reacting slowly and the like, see your health-care provider to get screened for what may be causing your symptoms. These include treatable psychological and medical conditions such as anxiety, depression, certain vitamin deficiencies or infections as well more serious neurological conditions including dementia.

How is brain fog diagnosed?

People experiencing brain fog often have their cognitive function evaluated with the Montreal Cognitive Assessment (MoCA), which involves drawing a clock, identifying pictures of animals and other simple tasks. Problem: The test can show whether there is evidence of a cognitive problem, but it cannot provide a specific diagnosis…and some people who complain of brain fog still score within the normal range of brain function.

What causes brain fog?

In addition to COVID and other infectious illnesses—especially those that cause prolonged fever—other potential causes of brain fog include lack of sleep, extreme emotional stress and even mild dehydration. Brain fog even can be triggered by overexposure to modern technology—frequent phone calls and texts and excessive screen time generally.

Other causes: Sometimes taking a new drug—or several drugs, a situation doctors call “polypharmacy”—can cause brain fog. Allergy medications, antidepressants, and opioids and other pain drugs are sometimes to blame. And as many cancer patients know, chemotherapy drugs are notorious for causing a form of brain fog called “chemo brain.”

If you suspect that a medication you’re taking might be the reason for your brain fog, ask your health-care provider if you can switch to a different drug or drugs…discontinue one or more drugs…or take a lower dosage. Pharmacists as well as physicians can be a key source of information about possible medication side effects, including those that might be associated with brain fog.

The following strategies may help to resolve brain fog…

• Lifestyle changes. Consider your lifestyle first. Prioritizing sleep, eating a brain-healthy diet and physical exercise can alleviate some of the symptoms of brain fog.
• Hydrate. Drinking more water and other nonalcoholic beverages—especially if you’ve had COVID or another infectious illness. The National Academies of Sciences, Engineering and Medicine recommends at least 15-and-a-half cups of fluid a day for men (a bit more than 125 ounces)…and about 11-and-a-half cups (a little more than 91 ounces) a day for women. Sometimes just having a glass of water can help clear your mind. Electrolyte-containing sports drinks, such as Gatorade, can help if you’ve been battling an infection or exercising, but be sure to watch the sugar in these drinks, and opt for sugar-free versions when possible.
• Eat right. Research from Rush University and other institutions suggests that the MIND diet—Mediterranean-DASH Intervention for Neurodegenerative Delay—can boost brain function and reduce risk for cognitive decline. The diet emphasizes consumption of beans, berries, green, leafy vegetables, nuts, whole grains, fish and olive oil…and discourages consumption of fatty and/or sugary foods, including red meat, cheese, fried foods, butter and margarine and sweets. Bottom line: What’s good for your heart is good for your brain.
• Exercise your brain. A 2024 study by researchers at George Mason University showed that a program called StrongerMemory, consisting of writing by hand, reading aloud and doing simple math exercises, boosted brain function among 102 older adults. StrongerMemory is available to older adults at no cost through the Goodwin Living Foundation. Other ways to exercise your brain include word puzzles, learning a new skill and/or attempting to do a task with your non-dominant hand.
• Get support. Psychotherapy and support groups can sometimes be helpful for people with long-term brain fog. And some brain fog sufferers find it useful to ask a friend or family member to act as an “accountability partner” to make sure tasks get done and appointments are kept. In addition to keeping a detailed daily calendar, some people with brain fog use a virtual assistant such as Amazon’s Alexa to keep track of their daily schedules.
• Consider medication…maybe. In some cases, certain medications help ease brain fog. Ask your doctor if you might benefit from taking an antidepressant or ibuprofen or another nonsteroidal anti-inflammatory drug (which can reduce inflammation in the brain and elsewhere in the body). For people whose brain fog may be associated with attention-deficit hyperactivity disorder (ADHD), a prescription stimulant drug such as methylphenidate (Ritalin) might be a good option. Vitamin supplements are unlikely to hurt—but also are unlikely to help unless you have a specific deficiency (your doctor can test your blood to find out).
• Other steps: If brain fog is making your work life difficult, explain your situation to your employer. Ask for any helpful accommodations—perhaps noise-blocking headphones or a quieter workspace could boost your focus. Maybe you need a bit more time to prepare for meetings or to complete tasks and assignments. Scheduling regular times to take a break and rest your brain also can be helpful. If keeping up with what’s being said in meetings is proving difficult, record the meetings so you can listen again later or obtain a transcript. If you encounter skepticism or pushback, ask your doctor to prepare a note describing your specific challenges and accommodations that might help.