IDO1 and Cognitive impairment: Symptoms like depression and impaired quality of life have also been proposed to be exacerbated by IFN-γ induced indoleamine 2,3-dioxygenase 1 (IDO1): as the subsequent degradation of Trp along the kynurenine pathway reduces the formation of serotonin, which can go along with heightened anxiety, cognitive deficits, and sleep disturbances22–26.