Several trends were identified in the mechanisms of FDA-approved drugs and those in Phase 3 trials for depressive disorders during this period, including NMDA receptor antagonism, kappa-opioid receptor antagonism, 5-HT1A receptor partial agonism, serotonin-norepinephrine reuptake inhibition, and the use of atypical antipsychotics as an adjunct to treatment with classical antidepressants. Here, HTR1A is linked to depressive disorder.