Medically Reviewed by Zilpah Sheikh, MD on August 28, 2023
What Is It?

What Is It?


“Brain fog” isn’t a medical condition. It’s a term used for certain symptoms that can affect your ability to think. You may feel confused or disorganized or find it hard to focus or put your thoughts into words.




Many women find it’s harder to remember things during pregnancy. Carrying a baby can change your body in lots of ways, and chemicals released to protect and nourish your baby may bring on memory problems.

Multiple Sclerosis (MS)

Multiple Sclerosis (MS)


This disease affects your central nervous system and can change the way your brain “talks” to the rest of your body. About half the people who have MS have issues with memory, attention, planning, or language. Learning and memory exercises can help, and a therapist can give you new ways to handle the tasks you have trouble with.  




Some kinds of drugs -- over-the-counter and prescribed -- can cause brain fog. If you take medicine and notice that your thinking isn’t as clear as it should be or you suddenly can’t remember things, call your doctor. Be sure to let them know all the medications you take. It is suspected that sensitivity to some chemicals (both natural and man-made) can also cause brain fog, a possibility that is debated in the medical community.. 

Cancer and Cancer Treatment

Cancer and Cancer Treatment


Chemotherapy -- a treatment for cancer that uses strong drugs -- can lead to what’s sometimes called “chemo brain.” You may have trouble remembering details like names or dates, have a hard time multi-tasking, or take longer to finish things. It usually goes away fairly quickly, but some people can be affected for a long time after treatment. Cancer itself can also cause “brain fog,” for instance, if the cancer has affected the brain.




Women may find it harder to learn or remember things when they reach this stage of life. It happens about a year after their last period, usually around age 50. Along with brain fog, they also may have hot flashes -- sudden sweating with a higher heart rate and body temperature -- and other body changes. Hormone supplements and other types of medication may help.

Chronic Fatigue Syndrome (CFS)

Chronic Fatigue Syndrome (CFS)


With this condition, your body and mind are tired for a long time. You may feel confused, forgetful, and unable to focus. There’s no known cure for CFS, but medication and talk therapy may help.




You may not remember things well or be able to think through problems easily. It’s hard to know if this is linked to the loss of energy and motivation that comes with depression, or if depression affects your brain in a way that causes the fog. Treatment for your depression, which includes medication and talk therapy, should help get you back on track.




You need sleep to help your brain work the way it should, but too much can make you feel foggy, too. Aim for 7 to 9 hours. To get good rest at bedtime, you may want to avoid caffeine and alcohol after lunch or right before bedtime and keep the computer and smartphone out of your bedroom. It also can help to get to bed and wake up at the same time every day. Talk to your doctor if you think your brain fog might be caused by a sleep disorder like apnea, insomnia, or narcolepsy.




This long-term disease causes your immune system to attack your body, and the symptoms can be different in different cases. About half the people with lupus have problems with memory, confusion, or trouble concentrating. There’s no cure, but medication and talking with a therapist can help.

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American Cancer Society: “Chemo Brain.”

Brain and Cognition: “Assessment of cognitive function across pregnancy using CANTAB: A longitudinal study.”

CDC: “Sleep and Sleep Disorders.”

Health “Brain Fog Causes.”

Journal of Hypertension: “Flavanol-rich chocolate acutely improves arterial function and working memory performance counteracting the effects.”

LiveScience: “Menopausal 'Foggy Brain' Confirmed in Tests.”

Lupus Research Alliance: “Can Lupus Affect My Brain?” “About Lupus.”

Mayo Clinic: “Chronic Fatigue Syndrome,” “Depression,” “Menopause.”

National Institutes of Health: “The Risks of Sleeping 'Too Much'. Survey of a National Representative Sample of 24671 Adults (INPES Health Barometer),” “What is brain fog? An evaluation of the symptom in postural tachycardia syndrome,” “Cognition in perimenopause: The effect of transition stage.”

National Sleep Foundation: “Debunking Sleep Myths: Does Alcohol Help or Hurt Your Sleep?”

Marin Optimal Health: “Brain Fog: Anxiety, Depression, Insomnia.”

American Sleep Apnea Association: “Brain Awareness.”

Nature and Science of Sleep: “New developments in the management of narcolepsy.”