The Easiest Way To Diagnose Brain Fog

Have you ever felt like your thoughts are trapped in a thick mental haze? Struggling to concentrate, recall words, or stay organized? You’re not alone. Brain fog has surged in recent years, affecting people of all ages—and researchers are scrambling to understand why. Could it be linked to long COVID, stress, sleep deprivation, or even something lurking in your bloodwork? The good news is that scientists are developing ways to test for brain fog, helping you uncover the root cause and take steps to regain your mental clarity. Read on to discover how you can finally diagnose and tackle brain fog once and for all.

Key Takeaways

• Brain Fog Has Many Causes – It can stem from long COVID, stress, sleep deprivation, hormonal imbalances, or nutrient deficiencies. Identifying the root cause is essential for proper treatment.
• Testing Can Pinpoint the Problem – Cognitive tests, blood work, and lifestyle evaluations can reveal deficiencies in vitamin B12, vitamin D, iron, thyroid function, or inflammation levels that contribute to mental fog.
• You Can Fight Brain Fog – Simple lifestyle changes, targeted supplements, medical treatments, and cognitive exercises can help restore mental clarity and focus.

The Hidden Causes of Brain Fog—and How to Find Out If You Have It

Researchers report that more people than ever now complain that they are suffering from brain fog – difficulties thinking, concentrating, and a frustrating inability to reliably focus their attention.

According to census data, the number of folks who say they wrestle with brain fog has climbed considerably in the last 15 years. And more younger people than ever have been complaining about it.

Much of this increase, researchers believe, is linked to the long-term neurological effects of COVID-19, although other lifestyle factors are also in play.

Understanding the Symptoms of Brain Fog and How To Test For It

Brain fog has been a difficult concept to pin down precisely. According to researcher Gabriel De Erausquin, MD, PhD, who is with the University of Texas Health at San Antonio, it is not really a medical term but a kind of catch-all description of thinking problems that include “poor concentration, confusion, thinking more slowly than usual, fuzzy thoughts and slower-than-usual short-term memory.”1

Often, says Dr. Erausquin, the kind of brain fog problems you may be having can vary depending on your age. For instance, in brain fog linked to COVID, younger, middle-aged people usually have difficulties with focusing their attention for long periods, can’t organize tasks very well, and find their executive function (coordination of mental activities) is disrupted. In older folks, brain fog from COVID more often directly messes up memory and interferes with their ability to carry on a conversation because it slows their recall of words and limits their vocabulary.

Think Faster, Remember More: How to Diagnose and Overcome Brain Fog

If you're suffering with chronic brain fog, your healthcare provider can help. They will check your medical history, perform a series of mental tests, and evaluate what is probably causing your brain fog problems while determining the seriousness and depth of your cognitive hiccups.

The tests for cognitive function can include tools such as the:

• Montreal Cognitive Assessment (MoCA): This 15-minute test is designed to assess memory, attention, executive function, language, abstract thinking, and visuospatial skills. 
• Mini-Mental State Examination (MMSE):  This test assesses five areas of cognitive function including orientation, information registration, attention and calculation, memory recall, and language and visuospatial skills.

It's also important to address common lifestyle factors that can cause or influence brain fog such as:

• Sleep habits: Lack of sleep and sleep interrupted by sleep apnea can cause or worsen cognitive issues. A wide range of studies show that when you skimp on sleep, your thinking processes go into low gear. So if you’ve had a long-term issue with insomnia or other sleep issues, you should seek professional help.2
• Stress: Research shows that an overload of stress interferes with your mental clarity. A review study by researchers in South America indicates that when your body releases stress hormones, they disrupt your ability to remember things clearly and age your brain faster.3
• Sitting for long hours every day: A lack of exercise and inactivity can contribute to brain fog. Research shows that moving around more and doing other activities can help your brain function better and lessen mental fogginess.4

Medical Tests for Brain Fog

Medical professionals can also evaluate your cognitive abilities with simple blood tests designed to measure physiological disturbances or deficiencies in your body that could be fogging up your thinking.

These include:

• Measuring your blood levels of nutrients like B12 and D and iron.
• Determining how well your thyroid is working. When thyroid function slips, your mental abilities may also slip.
• Calculating if inflammation could be disrupting your brain function. A high level of C-reactive protein in your blood indicates chronic inflammation.
• Identifying potential hormone issues that can lead to brain fog. For instance, research shows that menopause leads to hormonal changes that interfere with cognition.
• Testing you for an autoimmune problem like celiac disease (a reaction to gluten from wheat, barley and rye). Autoimmune diseases have been linked to brain fog.5
• Checking for viral infections such as COVID-19.

Track Your Mental Clarity At Home

If you're suffering from foggy thinking, it's important to track your symptoms and potential triggers. Take stock of your diet, sleep patterns, and stress levels. Note when your brain fog worsens or improves. For example, are you suffering most after meals or during certain times of the day or activities? 

In addition, log any medications and supplements you're taking and see if you can identify related patterns.

If you’re plagued by brain fog, you don’t have to throw in the towel and think that you can’t do anything about it. Some of these tests, along with an analysis of your daily habits, could identify the source of your problem.

Learn more about solutions to common causes of brain fog.

Summary

Brain fog—characterized by forgetfulness, difficulty concentrating, and slowed thinking—is becoming increasingly common, especially after COVID-19. While brain fog is not a medical condition itself, researchers are finding ways to diagnose and assess its severity. Medical professionals now use cognitive assessments, lifestyle evaluations, and blood tests to identify underlying causes such as vitamin deficiencies, thyroid dysfunction, inflammation, or hormonal imbalances. Understanding the specific cause of your brain fog is the first step to finding effective solutions, whether through lifestyle changes, medical intervention, or cognitive therapies.

Frequently Asked Questions

• What exactly is brain fog?
  Brain fog is a term used to describe cognitive difficulties like forgetfulness, lack of focus, slow thinking, and confusion. It’s often linked to stress, lack of sleep, inflammation, and other health conditions.
• How do doctors test for brain fog?
  Medical professionals may use cognitive assessments, memory recall tests, problem-solving challenges, and blood tests to check for deficiencies, inflammation, or hormonal imbalances affecting brain function.
• Can long COVID cause brain fog?
  Yes. Many people experience lingering cognitive issues after COVID-19, affecting memory, focus, and mental processing speed. Researchers believe inflammation and immune system overactivity may play a role.
• What lifestyle habits contribute to brain fog?
  Poor sleep, high stress, lack of exercise, poor diet, and excessive screen time can all contribute to brain fog. Addressing these factors can often improve mental clarity.
• Can brain fog be reversed?
  In many cases, yes. Identifying the root cause—whether it's a nutrient deficiency, hormonal imbalance, or poor lifestyle habits—can lead to treatments that significantly improve cognitive function.