EPO and major depressive disorder: Taking an unusual reverse approach (human trials first), we reported that EPO treatment has potent neuroprotective and procognitive properties in patient groups as different as ischemic stroke, chronic schizophrenia, chronic progressive multiple sclerosis, treatment-resistant major depression and bipolar disease (Ehrenreich et al. 2007a; Ehrenreich et al. 2007b; Miskowiak et al. 2014a; Miskowiak et al. 2014b).