Based on these experiments [77–79], we can speculate that the LHb interacts with the 5-HT system, modulates N-methyl-D-aspartic acid (NMDA) and aminomethyl phosphonic acid (AMPA) receptors, and has a bidirectional connection with the HPA axis to regulate the stress-related adaptive response to depression. This evidence concerns the gene LHB and major depressive disorder.