Recent studies have shed light on the involvement of glutamate pathways in the pathophysiology of TRD, mood disorders, and PTSD, and both ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, and psilocybin, a 5-hydroxytryptamine receptor 2A (5-HT2A) agonist, have emerged as promising options due to their ability to augment glutamate release. The gene discussed is HTR2A; the disease is treatment resistant depression.