In recent years, two neuropeptides (NPs) namely oxytocin (OT) and arginine vasopressin (AVP), have gained attention due to their role in neuropsychiatric conditions, such as depression, anxiety, autism spectrum disorder (ASD), attentional hyperactivity deficit disorder (ADHD), substance abuse disorder (SUD), etc. The development of novel pharmacological treatments for the aforementioned pathologies, is a relevant task since most of the current therapies exhibit low success rates and a time gap between the beginning of the treatment and the first reported positive outcomes by patients [1,2]. This evidence concerns the gene AVP and major depressive disorder.