These results suggest that the behavioral abnormalities in Fads(Δ/+) mice (i.e., the HABs and depression-like episodes) were due not to reduced FADS1/2 activity in the neurons or astrocytes but to reduced FADS1/2 activity in the periphery or microglia and endothelial cells in the brain where NC did not work. Here, FADS1 is linked to major depressive disorder.