Brain Fog

Brain fog is not a formal medical diagnosis but an umbrella term for cognitive (thinking and memory) difficulties. Brain fog can arise from specific environmental factors, like stress or sleep deprivation, or be a symptom of an underlying health condition. It can also be a side effect of a medication.

This article reviews the symptoms, causes, evaluation, and treatment of brain fog. It also provides insight into when to see a healthcare provider for this sometimes debilitating symptom.

Symptoms of Brain Fog

Brain fog involves a constellation of cognitive symptoms, including: 

• Difficulty thinking or focusing
• Problems finding the right words or processing what others are saying
• Forgetfulness or short-term memory loss
• Challenges with multitasking, planning, and organizing
• Feeling mentally "cloudy," "spacey," or "fuzzy"
• Easily distracted or disoriented

If brain fog is related to an underlying health problem, additional symptoms related to that condition may also be present.

For example, brain fog is commonly reported in individuals with long COVID-19. Individuals with long COVI-19 may also experience muscle aches, dizziness, headache, and changes in smell and taste.

Causes of Brain Fog

Various environmental factors/scenarios can lead to brain fog. These include:

• Stress
• Lack of sleep
• Prolonged standing
• Poor nutrition (e.g., vitamin B12 deficiency)
  
• Hormonal shifts in the body (e.g., menopause)

Brain fog can also be a symptom of an underlying health condition.

Examples of medical diagnoses associated with brain fog include:

• Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is associated with persistent and often disabling fatigue, non-refreshing sleep, and cognitive problems.  
• Fibromyalgia causes widespread muscle pain, as well as mood, sleep, and cognitive problems.
• Viral infections—for example, COVID-19 or human immunodeficiency virus (HIV) infection—can cause mental fatigue and various cognitive disturbances.
• Postural orthostatic tachycardia syndrome (POTS) causes faintness and light-headedness upon standing up. Fatigue and cognitive problems are additional symptoms.  
  
• Autoimmune diseases occur when the body's immune system mistakes healthy tissue for a foreign invader and attacks it.

The reason why brain fog develops among the above scenarios/conditions remains unknown.

Experts theorize possible causes include:

• An inflammatory response within the brain
• Impaired brain energy metabolism
• Decreased blood flow within the brain
  

What Medications Can Cause Brain Fog?

Several medications can cause brain fog as a side effect.

Examples of such medications include:

• Sleep aids, such as the prescription drug Ambien (zolpidem) or over-the-counter (OTC) Benadryl (diphenhydramine)
• Anticholinergic drugs, such as the tricyclic antidepressant Elavil (amitriptyline)
• Opioid analgesics, such as Norco (hydrocodone)
• Antianxiety medications, such as Xanax (alprazolam)
• Anti-seizure medications, such as Topamax (topiramate)
• Chemotherapy drugs (brain fog as a side effect is often called "chemobrain")
  

Contact your healthcare provider if you are taking any of these medications and experience brain fog.

How to Treat Brain Fog

The treatment of brain fog depends on its underlying cause.

Brain fog may go away with simple strategies like stopping a medication, taking a vitamin supplement, or getting a restful night's sleep.

Brain fog related to health conditions, however, may take weeks to months to improve or resolve. It can even be lifelong, ebbing and flowing with the nature of the underlying disease.

Depending on the health condition, a healthcare provider may recommend different therapies. 

For example, transcranial direct-current stimulation (a painless procedure that delivers electric currents to specific brain parts) may improve brain fog in fibromyalgia.

Likewise, a strict gluten-free diet can resolve brain fog in celiac disease. Intravenous (through a vein) saline has been found to reduce brain fog in POTS.

There are also general strategies for easing brain fog related to almost any condition or factor. These strategies may benefit those dealing with brain fog related to autoimmune diseases or viral infections.

• Getting enough sleep
• Engaging in regular exercise, which can start gently (e.g., walking or yoga) and increase as tolerated
• Adopting healthy eating patterns, like the Mediterranean diet
• Managing stress well, such as brief, daily meditation sessions
• Maintaining relaxing, fulfilling social connections
  

Are There Tests to Diagnose the Cause of Brain Fog?

No single test can diagnose the cause of brain fog. Instead, healthcare providers collect information from a person's medical history, physical examination, and various diagnostic tests.

Maintaining a sleep log or journal that documents your daily activities, meals, symptoms, and stresses can also help your doctor get to the bottom of your brain fog.

Diagnostic tests your healthcare provider may utilize include:

• Blood tests to understand possible brain fog causes (e.g., vitamin B12, COVID-19 antibody test, or thyroid stimulating hormone).
• Brain imaging tests, like magnetic resonance imaging (MRI), to evaluate for neurological conditions.

Individuals with brain fog may also be referred to various specialists, like a sleep specialist or psychologist, to rule out mimicking or contributing conditions (e.g., sleep apnea or depression, respectively).

When to See a Healthcare Provider

Contact a healthcare provider if your brain fog strikes suddenly, impairs your ability to function daily, or is worsening.

Additionally, contact your healthcare provider if you recently started a new medication or are experiencing the worsening of an underlying health condition related to brain fog.

Also, seek medical attention immediately if you are experiencing brain fog associated with worrisome symptoms like new or frequent headaches, fainting, or stroke-like symptoms (e.g., arm or leg numbness or weakness).

Summary

"Brain fog" is a general term for an array of cognitive symptoms. It may be a response to a medication or certain environmental factors, like stress or lack of sleep, or stem from an underlying health condition.

A detailed medical history, physical exam, and various tests, like blood or imaging studies, are used to evaluate brain fog. Treating brain fog depends on the root cause and may involve lifestyle and medical strategies.