HCRT and major depressive disorder: Our results suggest a substrate of resilience, namely, the neuropeptides orexins, which are known to mediate the stress response and are altered in patients with MDD and PTSD (Kuru et al., 2000; Yehuda, 2000; Winsky-Sommerer et al., 2004; Spinazzi et al., 2006; Furlong et al., 2009; Strawn et al., 2010; Chen et al., 2015a).