A 2009 study by University of Calgary researcher Mark Swain, MD, and colleagues offers a potential explanation for why inflammation in distant parts of the body may induce brain fog. By studying lab mice, Swain and his team found that inflamed body tissues (in this case, inflamed livers) transmit signals to the brain that can produce symptoms such as malaise and fatigue. Swain explains that chronic inflammation can “activate” immune cells in the bloodstream, causing them to enter the brain and release proteins called cytokines. Normally, these proteins help regulate how your immune system responds to threats such as infections. But inside the brain, cytokines may alter the quantity and activity of critical chemical messengers known as neurotransmitters. “When you alter neurotransmitter systems, you can change behavior, emotion, your desire to get up and go,” says Dr. Swain.

Clearing the Fog

Unruly cytokines cause more than brain fog, of course. Cytokines such as tumor necrosis factor (TNF) and interleukin-6 (IL-6) promote joint inflammation, which is why newer RA drugs known as biologic agents were designed to block them. Interestingly, RA patients who had previously complained of fatigue and mental lethargy often say they feel like their old selves soon after they start receiving TNF inhibitors (such as etanercept or adalimumab) or other biologic agents — even before their joint pain improves.

“It can be within an hours of receiving treatment,” says Dr. Swain. In fact, last year a preliminary study in the United Kingdom found an improvement on IQ test scores among 15 RA patients given adalimumab.

Getting pain and stiffness of RA under control also helps patients sleep better, which has the ripple effect of making people feel sharper, points out rheumatologist David Borenstein, MD, a clinical professor of medicine at George Washington University Medical Center in Washington, D.C.

“Patients will say ‘I have trouble thinking because I’m so tired,’” notes Dr. Borenstein. But adding a biologic agent to their regimen helps them get more restorative shut-eye. “Suddenly they’re saying, ‘I don’t need to take a nap in the afternoon anymore. I feel energized.’”

Dr. Borenstein says it’s also important for RA patients who feel foggy-brained to improve their sleep habits by taking steps such as limiting caffeine consumption to the morning and not exercising close to bed time. But do get plenty of physical activity, he advises, which causes the body to generate endorphins and other mood-boosting hormones. “They make you feel better,” says Dr. Borenstein.  

Rissenberg says that people with illness-related cognitive problems can offset the effects of brain fog with certain strategies, such as using a day planner and sticking to routines to help overcome forgetfulness or lack of motivation. Some people find that they’re more clear-headed at certain times of the day; reserve those periods for tasks requiring you to stay focused and alert.

Above all, take care of yourself. “Work on whatever enhances your wellness,” says Rissenberg, “because that will improve your cognition.”