HCRT and major depressive disorder: Given that VP is also implicated in emotion and stress resilience [4–6], and orexinergic neurons are likely to promote adaptive behaviors in response to acute stress, such as improving avoidance performance in shock-associated contexts or increasing the time spent in safe and enclosed zones in an unfamiliar environment [51, 55], we propose that orexin and central orexinergic system may prevent depression by promoting stress resilience.