An imbalance of n-6 and n-3 FA has been suggested to cause an overproduction of proinflammatory cytokines (such as IFNγ, TNFα, IL-6, and IL-1) and may lead to changes in serotonin (5-HT) and dopamine receptor (DR-2) number and function [59,60], thereby contributing to the cause of major depressive disorders. This evidence concerns the gene TNF and major depressive disorder.