Brain fog

• Attention
• Concentration
• Learning
• Short-term memory

What that might look like can differ between people, but here are some things you may experience as a consequence of brain fog, according to Pudumjee and Danielle Wilhour, MD, an assistant professor in neurology at the University of Colorado School of Medicine in Denver:

• You struggle with multitasking.
• You have more trouble grasping concepts or learning compared with before.
• Words arrive at the tip of your tongue, but you can’t seem to find them.
• You may feel as if you’re in a dream or trancelike state.
• You walk into a room and can’t remember what task you set to accomplish.
• You forget details of conversations.
• You can’t absorb content as well as you used to.
• You’re easily pulled off task or distracted.

Pudumjee also says that patients describe a general feeling of cognitive sluggishness. In one study that examined the use of the term “brain fog” in Reddit posts, people described this experience with a range of descriptors, including “dissociation, fatigue, forgetfulness, and excessive cognitive effort.” These symptoms can all combine to give you the feeling that your thinking is cloudy.

Possible Causes of Brain Fog

One of the challenges with understanding brain fog is that there are so many potential causes, and having brain fog alone doesn’t tell doctors what exactly is going on. That said, here are a few common causes to consider.

Hormonal Changes

Menopause and pregnancy can both contribute to brain fog, says Dr. Wilhour. Research shows that people who are pregnant report confusion, disorientation, and fogginess, which lead to behaviors such as putting things down in odd places, misplacing belongings, and forgetting simple work tasks. (Some call this “pregnancy brain.”)

As for menopause, one study explains that difficulty with memory can begin early on in menopause and end in postmenopause, likely due to the effects that estrogen has on memory performance.

Diet Challenges

If you’re eating a restricted diet, not consuming adequate vitamins and minerals may result in experiencing some brain fog, says Pudumjee. Specifically, a deficiency in B12 or iron can cause anemia, which can decrease your energy levels and tangentially affect cognition, says Wilhour.

In addition, food allergies and sensitivities may also change your cognitive capabilities, Wilhour notes. According to Beyond Celiac, 95 percent of people in its research with nonceliac gluten sensitivity report having brain fog.

Medications

Taking medication may include side effects related to brain fog. For example, topiramate (Topamax), which is used to treat migraine, can leave you feeling mentally murky. “I warn patients that it can cause cloudy thinking, confusion, and word-finding difficulty,” Wilhour says. In addition, taking multiple medications — also called polypharmacy — can be another factor in brain fog, she says. People experience side effects in different ways, but if you’ve noticed that brain fog has occurred after starting a new drug, ask your doctor or pharmacist if cognitive issues are a possible side effect. (Don’t stop taking prescribed meditation without first consulting your physician.)

Chemotherapy

“Chemo brain” is a well-known phenomenon that describes thinking problems before, during, and after cancer treatment, according to the National Cancer Institute. This mental fog can be caused by the cancer itself, conditions caused by cancer (such as depression or sleep problems), or a variety of treatments including chemotherapy, radiation, and hormone therapy.

Certain Medical Conditions

Wilhour notes that brain fog may emerge with many medical conditions, including postural orthostatic tachycardia syndrome, anemia, diabetes, depression, anxiety, and autoimmune conditions such as multiple sclerosis, chronic fatigue syndrome, celiac disease, and lupus.

One common disease associated with cognitive troubles: hypothyroidism, or an underactive thyroid, which affects 5 percent of Americans older than 12, per the National Institute of Diabetes and Digestive and Kidney Diseases. Fatigue, depression, and difficulty with memory and executive function are often an early sign of hypothyroidism, according to research.

Separately, researchers have found that more people with mild cognitive impairment (MCI), as opposed to those without, may develop Alzheimer’s disease or dementia, according to the National Institute on Aging. Roughly 10 to 20 percent of people 65 and older with MCI develop dementia over a yearlong period, however, studies underway aim to understand why some people with MCI progress to dementia and others don’t.

COVID-19

COVID-19 is known to cause lingering problems with attention, concentration, and memory after infection, one symptom of long COVID, according to the National Institutes of Health (NIH). This may be due to inflammation in the brain that affects how brain cells behave, according to NIH-supported research.

In one study, 7.2 percent of people who reported having long COVID experienced brain fog, and this symptom was more common in women, those who had preexisting respiratory problems, and those who had a more severe case of COVID-19.

Additionally, according to several neuroscientists and behavioral experts, the trauma and isolation some people experienced during pandemic-related lockdown may also have been a contributing factor to brain fog, notes an article in The Guardian.