HCRT and obesity due to melanocortin 4 receptor deficiency: Conversely, orexin release maintains wakefulness and increased orexin levels correlate with weigh reduction in adolescents [84], indicating that increased orexin signaling promotes obesity resistance (for review on the relationships between orexin and body weight, see Sakurai [85], Perez-Leighton et al. [86], Mahoney et al. [87]).