Is Depression a Systemic Inflammatory Disease?
How can exercise and fish oil often be a more effective treatment for depression than antidepressants? Could it be because they are both potent anti-inflammatories? Could it be that depression is a low-grade inflammatory disease of the brain 1? Let’s look at the evidence1. • Proinflammatory cytokines IL-1, IL-6, and TNF α (molecular messengers that set off the inflammatory response) and bacterial toxins (produced in our gut) produce symptoms of depression and anxiety. • Cytokines overactivate the HPA (hypothalamic-pituitary-adrenal) axis (the stress response) just like we find in depressed patients. • Cytokines increase the function of an enzyme (IDO) that breaks down tryptophan, leading to less serotonin in the brain3. Serotonin is the happy mood chemical that fights depression. • The immune system is overactive in severe depression, producing brain inflammation. • Using immune therapy like interferon (a cytokine) for diseases like hepatitis C or multiple sclerosis triggers depression
