A study that sought to find the association between BMI, orexin, and leptin levels in NT1 patients divided into low orexin levels (26 cases) and normal orexin levels (23 cases), and compared them with 46 healthy controls matched for sex and age [81], reported a statistically significant increase in the number of obese patients (BMI > 30) in narcolepsy compared with controls. Here, LEP is linked to narcolepsy.