Causes of Brain Fog: What are the Reasons for My Brain Fog?

The causes of brain fog are numerous. Learn about brain fog causes so you can reduce or eliminate brain fog from your life. Details on HealthyPlace.

Many causes of brain fog are at work when you feel like you’re unfocused and confused, stuck in a thick cloud, everything—including your own thoughts—just out of reach (Symptoms of Brain Fog: What Does Brain Fog Feel Like?). Brain fog isn’t an illness by itself; instead, it’s a condition that can occur with many different mental- and physical health problems. The biggest factor in brain fog is brain fatigue. Knowing what exhausts your brain enough to cause brain fog will help you understand the reasons for your brain fog.

Brain fog causes are numerous and can include such things as:

  • Medical conditions
  • Psychological conditions
  • Stress
  • Lack of sleep
  • Too much sleep
  • Hormonal changes
  • Diet
  • Some medications
  • Chemotherapy
  • Alcohol consumption
  • Exposure to toxins
  • Allergies
  • Inflammation in the body
  • Caffeine withdrawal

Let’s explore what causes brain fog a bit more closely.

Causes of Brain Fog: Psychological and Medical Conditions

When something isn’t right in the body or brain, you might experience brain fog as part of the condition you’re dealing with. Both mental illness and physical illness can cause brain fog.

Numerous mental health challenges or mental illnesses can muddle thinking, lead to disorientation, confusion, and memory loss, and cause difficulties in focusing and concentrating.

While this list isn’t exhaustive, some of the biggest mental health causes of brain fog are

  • Depression
  • Bipolar disorder
  • Anxiety
  • PTSD
  • Unprocessed trauma from the past
  • Emotional shock (an acute stress reaction to an upsetting event or situation)
  • Adult ADHD

Any of the above experiences can tax the brain. Some cause chronic stress on the physical brain, while others cause sudden, acute stress. Stress is wearing on the brain. It has difficulty dealing with extreme or chronic stressors and becomes fatigued. You feel this fatigue as brain fog.

Medical conditions (physical illnesses) can exhaust the brain just as much as mental health struggles. Among the most common causes of brain fog that relate to physical health:

  • Fibromyalgia
  • Chronic fatigue syndrome
  • Diabetes
  • Autoimmune diseases (rheumatoid arthritis, lupus, multiple sclerosis, etc.)
  • Hypothyroidism
  • Migraines
  • Alzheimer’s diseases
  • Anemia
  • Cancer/Chemotherapy

Brain fog causes can involve hormonal fluctuations, especially in women. Pregnancy, menstruation, and menopause all can cause upheaval and contribute to brain fog.

Brain fog can be a side-effect of medication. If you are experiencing brain fog and taking medication for any reason, even if it’s not on one of the above lists, you might consider checking in with your doctor or psychiatrist. Eradicating your brain fog could be as simple as switching medications or adjusting dosages.

Brain Fog Causes: Stress

Stress is a big contributing factor to brain fog. Whether it’s acute or chronic, stress overstimulates the brain. It can overwhelm the nervous system. Stress can negatively impact all systems of the body. Given that the organ responsible for governing the entire body is the brain, stress can leave the brain fatigued.

In response to stress, the brain orchestrates the production and release of stress hormones like cortisol, adrenaline, and norepinephrine. These hormones, though, are more brain fog causes. They contribute to the difficulty with focusing, concentration, thinking, speech, and memory that are all part of brain fog.

Something else that can be a cause or an effect of stress, mental health conditions, and medical conditions is sleep. The brain needs the proper amount of sleep, especially given that so many things we deal with can cause brain fatigue. Too little sleep, as well as too much sleep, make it difficult for the brain to function well. Sleep problems are one of the most significant causes of brain fog.

Managing stress and practicing good sleep hygiene can drastically reduce brain fog. Learn stress management techniques, with self-help books or with a mental health therapist, to blow away brain fog and increase the quality of your life.

Causes of Brain Fog: Improper Nutrition

Nutritional deficiencies and dehydration are frequent culprits of brain fog. The brain requires nutrients to function properly, and without them, it will suffer and become tired. You’ll experience brain fog.

Brain fog causes involving diet include:

  • Processed junk food
  • Sugary drinks like sodas and coffee drinks
  • Refined sugars in desserts, other sweets
  • Fast food
  • Refined breads and pastas
  • Trans fats
  • Additives (like MSG, sucralose, aspartame, etc.)
  • Overeating
  • Unstable glucose levels that spike and crash (usually due to simple carbohydrates like sugars and refined foods)

Eating foods to which you are allergic, sensitive, or intolerant can cause brain fog, too. Plain yogurt with probiotics, for example, is healthy for the brain, but if you are sensitive to dairy, this healthy food could cause brain fog. Opt for other brain-friendly foods instead (Brain Fog Supplements, Vitamins, Remedies: Hoax or Real Deal?).

Brain fog reasons are numerous. Knowing what they are can help you make lifestyle changes to get rid of brain fog and feel like you’re part of your world again.

article references

APA Reference
Peterson, T. (2021, December 30). Causes of Brain Fog: What are the Reasons for My Brain Fog?, HealthyPlace. Retrieved on 2024, July 18 from

Last Updated: January 9, 2022

Medically reviewed by Harry Croft, MD

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