At one point or another, you’ve likely experienced that fuzzy, “out of it” feeling; perhaps after not getting enough sleep or having one too many drinks. While occasional bouts of “brain fog”—especially those that come after a rough night— are common, chronic brain fog can affect day-to-day functioning and potentially even diminish quality of life, notes the American Psychiatric Association (APA).

Keep reading for common causes of brain fog, including ways to treat it and when it might be time to seek professional help.

What Is Brain Fog?

Brain fog is a general, non-medical term used to describe a subjective sense of cognitive impairment that may manifest in a number of ways. It’s often characterized by issues with memory, difficulties with concentrating or thinking, being easily distracted and feeling mentally clouded. It can affect people’s daily routines, such as work, school and relationships with others, and it may affect one’s mood and emotions.

“Brain fog is a mild and temporary cognitive impairment that involves difficulties with concentration, word finding and memory,” explains Anson Whitmer, Ph.D., co-founder of Mental, a mental health app geared towards men. Some examples of brain fog can include forgetting what you were talking about, scrambling for a word or struggling to focus on a task at hand.

“Generally, instead of feeling as cognitively sharp and clear as you normally are, you feel cognitively sluggish,” Dr. Whitmer adds. “Mental tasks are harder than normal.”

5 Causes of Brain Fog

There is no singular cause of brain fog. Instead, there are many possible reasons one is experiencing cognitive delays and impairments. These reasons may include the following:

Stress

Stress can wreak havoc on one’s daily life in various ways, particularly when it comes to cognitive function.

“Stress can cause a reduction in the brain’s ability to process information and make decisions due to increased blood pressure or a weakened immune system,” says Gurneet Singh Sawhney, M.Ch., a consultant neurosurgeon and spine surgeon at Fortis Hospital in Mumbai.

In fact, a 2017 study notes the profound effect stress has on the body’s nervous system, and that it can even cause structural changes to the brain, leading to changes in memory and cognition. Overall, researchers note that the effects of stress on cognitive function vary and are typically based on factors such as timing and intensity, but in general, intense stress can cause cognitive disorders, particularly in memory and judgment^[1].

Sleep Habits

If you’ve ever spent a night tossing and turning only to feel bleary-eyed and struggling to power through the next day, you likely understand the powerful connection between sleep and cognitive function. But some research suggests sleeping too much may have an impact, too.

In one 2017 study in Sleep, 10,000 participants completed tasks in three cognitive domains—short-term memory, reasoning ability and verbal ability—and were asked about their sleep patterns. Researchers found that roughly half of all participants who had slept less or more than seven to eight hours per night displayed impaired cognitive function.

Notably, the research also found that sleeping just four hours a night was equivalent to aging eight years, and that sleeping more than usual (and closer to the optimal amount) before cognitive testing was associated with better performance—underscoring just how powerful a good night’s rest can be^[2].

The Centers for Disease Control and Prevention (CDC) recommends that adults ages 18 to 60 aim for at least seven hours per night, although the ideal amount of sleep varies from person to person. Infants, young children and teenagers should get more sleep in order to support growth and development.

Poor Nutrition

While foods rich in vitamins, minerals and antioxidants support cognitive function and protect the brain from oxidative stress, low-quality foods, such as processed and refined foods, can negatively impact it. Refined sugar in particular promotes inflammation and oxidative stress.

One 2022 study in Nutrients found that certain food components, including saturated fatty acids and simple sugars, contribute to the decline of cognitive health (particularly impacting progressive learning and memory performance), even more so than excessive calorie intake^[3].

Medication

Many medications have side effects, some of which may affect the brain, particularly memory. Some medications that can cause memory and confusion include tricyclic antidepressants, anti-anxiety medications, anti-seizure drugs, opioid analgesics and more.

COVID-19

A COVID-19 infection is another possible cause of brain fog, primarily as a symptom of long COVID—the instance in which symptoms of COVID-19 symptoms occur months after infection.

“Many people who have recovered from COVID-19 report persistent cognitive problems, such as memory loss, difficulty concentrating, confusion and mental fatigue,” says Dr. Sawhney.

Indeed, a 2022 systematic review of over 11,000 patients with post COVID-19 symptoms (defined as symptoms that developed or persisted three or more months after COVID-19 infection) found that fatigue and cognitive dysfunction—particularly brain fog, memory issues and attention disorder—were the key features of post-COVID-19 syndrome^[4].

Brain Fog vs. Dementia

Dementia is a general term that describes prominent loss of memory along with deterioration in language, problem solving and other thinking abilities that are severe enough to interfere with daily life. Alzheimer’s disease is the most common cause of dementia, but there are other causes as well. Dementia is not a normal part of the aging process—although it does affect millions of older adults, notes the CDC. For older adults experiencing brain fog, the symptom overlap with dementia may be concerning. However, the two are vastly different.

Dr. Whitmer reminds that brain fog is not a condition but rather a cluster of symptoms that is temporary, while dementia points to damage in the brain that is permanent and progressive.

A key difference between dementia and brain fog is the extent that it affects someone’s life. People with dementia, for example, can struggle with functional aspects of daily life such as managing household finances, engaging in social activities and basic household tasks.

How to Treat Brain Fog

“Treatment of brain fog largely depends on its underlying causes,” notes Wei “Erik” He, M.D., a neurologist at Katy Neurology affiliated with Memorial Hermann Mischer Neuroscience Associates in Katy, Texas.

That being said, there are some general steps one can take to help improve cognitive function, according to Dr. Singh, such as:

• Getting enough sleep. This should also include avoiding stimulants such as caffeine, alcohol, nicotine and screens before bed.
• Managing stress. Practicing relaxation through breathwork or meditation as well as seeking professional help from a mental wellness facilitator can assist in mitigating stress.
• Eating a healthy and balanced diet. Be sure to have a proper diet that consists of foods that contain vitamin D and vitamin B12, as well as minerals such as zinc and magnesium to help ensure your body is getting what it needs.
• Exercising. Engaging in a regular routine can improve blood circulation and oxygen delivery, as well as help to reduce stress.
• Stimulating the brain. Challenging the brain with activities that are centered on problem-solving, memory and logic can help keep your mind activated. Activities such as learning a new skill or language, working on a puzzle, playing games that involve memory or reading all can be helpful in challenging the brain.
• Medication treatment. Experts note that there may be some medication options that help increase brain function. It’s important to visit with the right medical specialist to discuss your options.

When to See a Doctor

Living with even occasional brain fog can be disruptive to anyone’s life. More importantly, as it can stem from any number of issues, one should be examined by a medical professional if it occurs with any sort of regularity.

Specifically, if you are experiencing any of the following symptoms, you should seek medical attention as soon as possible, as it may be a more serious issue, notes Dr. Whitmer:

• Forgetting how to do daily tasks
• Forgetting important events
• Atypical aggression or other personality changes
• Hallucinations
• Prolonged confusion

Dr. He adds to also seek medical attention if symptoms worsen or begin without any obvious cause.

Sources:

Footnotes:

1. Yaribeygi H, Panahi Y, Sahraei H, Johnston TP, Sahebkar A. The impact of stress on body function: A review.EXCLI J. 2017;16:1057-1072.
2. Wild J, Nichols E, Battista M, Stojanoski B, Owen A. Dissociable effects of self-reported daily sleep duration on high-level cognitive abilities. 2018;41(12).
3. Fadó R, Molins A, Rojas R, Casals N. Feeding the Brain: Effect of Nutrients on Cognition, Synaptic Function, and AMPA Receptors. 2022;14(19):4137.
4. Premraj L, Kannapadi NV, Briggs J, et al. Mid and long-term neurological and neuropsychiatric manifestations of post-COVID-19 syndrome: A meta-analysis.J Neurol Sci. 2022;434:120162.

References:

1. Brain Fog vs. Dementia. Oregon Health & Science University. Accessed 8/26/2023.
2. Nutritional Psychiatry: Your Brain On Food. Harvard Medical School. Accessed 9/20/2023.
3. Stuck in a Brain Fog? Look in Your Medicine Cabinet. Harvard Medical School. Accessed 9/20/2023.
4. About Dementia. Centers for Disease Control and Prevention. Accessed 9/20/2023.