(4) Sirt1/MAO-A: 5-HT is primarily found in vesicles at the ends of 5-HT neurons, and current research on 5-HT targets for the treatment of PTSD has focused on selective serotonin reuptake inhibitors (SSRIs) and monoamine oxidase inhibitors (MAOIs; Auxéméry, 2012). This evidence concerns the gene MAOA and post-traumatic stress disorder.