It is not clear whether this is a direct result of the pathological background of the disease (lack of orexin neurons, deficiency of orexin) or of other clinical features of narcolepsy (obesity, less intense physical activity, disturbed nocturnal sleep) or maybe this is a consequence of therapy with stimulants [70]. The gene discussed is HCRT; the disease is obesity due to melanocortin 4 receptor deficiency.