A nocturnal SOREMP does not only enter in the count of the MSLT SOREMP to confirm narcolepsy diagnosis (either NT1 or NT2), but, in the presence of ‘typical’ cataplexy, can be the only neurophysiological marker for NT1 diagnosis, according to the latest ICSD‐3‐TR (American Academy of Sleep Medicine 2023), given its high specificity for CSF‐HCRT1 deficiency (Reiter et al. 2015; Andlauer et al. 2013). Here, HCRT is linked to narcolepsy.