In a study of more than three million people, those who were hospitalized for an autoimmune disease were 45% more likely to develop a mood disorder later on. The risk jumps to 62% if they were hospitalized for an infection, and it increases even further if they were hospitalized for both. So why, if an infection is wiped away with antibiotics and if an autoimmune disease is stabilized, do they haunt us? All signs point to a rather buzzy health topic: inflammation. When the immune system is activated, proteins called cytokines are released and continue to communicate with the brain. But over time, they can alter your behavior. “Inflammatory cytokines act in the brain to reduce serotonin activity that is associated with depression,” says Michael Irwin, MD, cousins professor of psychiatry and biobehavioral sciences at UCLA. Most depression drugs aim to increase serotonin activity, just the opposite of what these proteins can do. It’s not news that depression and immunity are linked—earlier this year, Irwin and his team found older adults with untreated depression are at a higher risk for shingles, a painful resurgence of the chicken pox virus, even after being vaccinated. What makes the present study important, however, is the prevalence. “Infections are very common, as well as autoimmune disorders,” says Irwin. “Identifying who is most at risk for new depression can translate into prevention treatments that could target a high risk group or inflammation itself.” Inflammation has been linked to serious health conditions like cancer, heart disease, and arthritis. Until the researchers know for sure if it is the culprit, it’s still a good idea to keep it in check with these 6 inflammation-fighting tips.
