POMC and post-traumatic stress disorder: Numerous studies have shown that ELS is positively associated with HPA axis hyperactivity in both healthy adults and individuals with depression and PTSD, as indicated by increased peripheral cortisol and dehydroepiandrosterone (DHEA) levels, enhanced cortisol awakening response (CAR), or increased ACTH and cortisol responses to environmental stressors or endocrine challenges [36,37,38,39,40,41].