Further studies addressing the identification of susceptibility genes for PTSD, like polymorphisms in the dopamine transporter gene [34] and in the promoter region of the 5-HT transporter gene [35], would greatly increase the understanding of stress-related disorders and contribute to the comprehension of their molecular basis and distinct neuroendocrine signature in individuals who report early life stress (ELS). Here, SLC6A4 is linked to post-traumatic stress disorder.