TNF and Anxiety: We are beginning to understand the interplay between cytokines, the immune system and mental health.1 53 At a molecular level we are aware that proinflammatory cytokines, including IFN, IL-1β and TNF, can reduce the availability of monoamines by inducing expression of presynaptic reuptake pumps and inhibiting enzymes involved in monoamine synthesis,54 linking the monoamine theory of anxiety with inflammatory mechanisms.