The NK-1R antagonist MK-869 has been shown to effectively suppress depressive behavior in guinea pigs, and both MK-869 and casopitant successfully completed phase II clinical trials to treat depression (Kramer et al., 1998; Ebner and Singewald, 2006; Di Fabio et al., 2013). The gene discussed is TACR1; the disease is depressive symptom measurement.