IL6 and major depressive disorder: To complicate the matter, altered immune functioning/inflammatory responses (e.g., levels of IL-6, TNF-α, and C-reactive protein), as well as the polymorphisms in IL6, IL1β, IL10, and TNFIα, appear to contribute to a potential increased susceptibility to depression, cognitive impairment, and dementia/Alzheimer’s disease [e.g., 445–452].