HCRT and narcolepsy: Due to the specificity and sensitivity of low CSF orexin levels (less than 110 pg/ml or 30% of the mean normal levels), narcolepsy–cataplexy is high among various sleep disorders [22, 24], and CSF orexin measures were a diagnostic criteria for narcolepsy–cataplexy in the 2nd and narcolepsy type1 in 3rd editions of the International Classification of Sleep Disorders (ICSD-3) [7].