Brain fog is a term used to describe cognitive difficulties such as memory problems, trouble focusing, or difficulty organizing thoughts, which can interfere with daily activities and overall quality of life.
It is not a medical diagnosis but rather a symptom that can occur in different conditions or situations. It is commonly seen in long COVID but can also be linked to lack of sleep, stress, fatigue, hormonal imbalances, autoimmune disorders, or nutritional deficiencies.
It’s important to see a primary care doctor if you experience these symptoms. The evaluation may include cognitive tests, lab work, and mental health assessments to rule out reversible causes and determine the most appropriate treatment.
Main symptoms
The most common symptoms of brain fog include:
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Difficulty concentrating and thinking clearly
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Memory problems
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Slower thinking and trouble learning new information
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Trouble finding words
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Difficulty with planning, organization, decision-making, and multitasking
Brain fog is often accompanied by extreme fatigue and a feeling of being mentally overwhelmed. It may also occur alongside anxiety or depression.
How it is diagnosed
The diagnosis of brain fog is based mainly on a clinical evaluation performed by a doctor to identify what’s causing the symptoms.
A detailed medical history, standardized cognitive tests, and lab tests may be done to check for nutritional deficiencies, hormonal changes, or metabolic disorders.
In some cases, brain imaging or psychological and psychiatric assessments may also be recommended, especially when neurological or mental health conditions are suspected.
The goal of diagnosis is to identify reversible causes and guide personalized treatment, which may include lifestyle changes or specific therapies depending on the underlying condition.
Causes of brain fog
Brain fog can be caused by several factors, including:
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COVID-19 infection
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Stress
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Lack of sleep
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Side effects of certain medications
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Chemotherapy
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Drug use
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Vitamin B12 deficiency
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Hormonal changes, such as during pregnancy or menopause
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Medical conditions like anemia, diabetes, hypothyroidism, chronic fatigue syndrome, fibromyalgia, or autoimmune diseases like lupus
It can also occur in people who have spent long periods in intensive care units or those who have experienced traumatic brain injuries.
Why COVID-19 causes brain fog
In COVID-19, brain fog appears to be related to inflammation in the body that affects the brain. This may be due to neuroinflammation, oxidative stress, changes in neurotransmitters such as serotonin and dopamine, dysfunction in brain microcirculation, and dysregulation of the hypothalamic-pituitary-adrenal axis.
The virus may damage the blood-brain barrier, allowing proinflammatory cells to enter the nervous system and interfere with normal cognitive processes.
Treatment options
Treatment for brain fog depends on its underlying cause. When a specific problem is identified, it should be treated appropriately—for example, using iron supplements for anemia or thyroid hormone replacement for hypothyroidism. In autoimmune conditions, doctors may prescribe corticosteroids or other immunomodulators.
Although supplements such as omega-3 fatty acids or multivitamins are sometimes recommended, they should always be used under medical supervision. Scientific evidence on their effectiveness for brain fog is limited, and they may interact with other medications.
Strategies to improve brain fog
In addition to treating the underlying cause, some lifestyle strategies can help improve brain fog:
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Reduce stress through meditation, yoga, or recreational activities
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Eat a balanced and nutritious diet
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Exercise regularly
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Avoid alcohol and drug use
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Break large tasks into smaller, manageable steps
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Use calendars or reminders to stay organized
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Challenge your memory with puzzles, crosswords, or Sudoku
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Keep important items in consistent places
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Minimize distractions during activities that require focus
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Sleep at least 7 to 8 hours per night
In persistent cases, cognitive rehabilitation with neuropsychological support or multidisciplinary programs can help improve memory, concentration, and quality of life, especially in people with long COVID, chronic fatigue, or autoimmune diseases.