Brain fog is a term used to describe feeling mentally unclear or unfocused. It can be caused by many things, such as medications, illness, lack of sleep, stress or anxiety. Brain fog is usually temporary and goes away once the cause is corrected. However, for some people it can be a more persistent problem.
How common is brain fog? A study published in the journal Headache found that 43 percent of people experience brain fog at least once a week. Brain fog can significantly impact quality of life, causing problems with concentration, memory, decision-making and communication.