The induction of proinflammatory cytokines, such as interleukin (IL)-1β, IL-6, IL-18, and tumor necrosis factor (TNF)-α, have all been associated with depression [20,25] and increased peripheral inflammation has been observed in many psychiatric diseases such as depression, anxiety, and even autism spectrum disorder (reviewed in [26]). Here, IL18 is linked to depressive symptom measurement.