However, studies with no association with changes in the TNFα level and symptoms of MDD have been published (Haapakoski, Mathieu, Ebmeier, Alenius, & Kivimäki, 2015; Karlovic, Serretti, Vrkic, Martinac, & Marcinko, 2012; Yoon, Kim, Lee, Kwon, & Kim, 2012). Here, TNF is linked to major depressive disorder.