HCRT and narcolepsy: Here, we report the results of the repeated assessment of CSF HCRT-1 levels in six patientswith narcolepsy symptoms and unexpected CSF HCRT-1 level (>100 pg/mL) at baseline.Moreover, it has been reported that the number of histamine (HA) neurons is increased in thetuberomammillary nucleus in patients with NT1,8,9 without changes in CSF HAor tele-methylHA (t-MHA) levels.10 Toour best knowledge, no study has described the temporal changes of CSF HA and t-MHA levelsin narcolepsy.