Narcolepsy, cataplexy, hypocretin and co-existing other health complaints: A review

The presence of cataplexy in people with narcolepsy has a well-documented tight association with very low or non-detectable levels of the central nervous system neuropeptide, hypocretin (also termed orexin) while levels of hypocretin are normal in people with narcolepsy without cataplexy. There is evidence to suggest that hypocretin may have an association with pain, migraines and headaches in people with narcolepsy. However, these studies have not compared findings across narcolepsy with and without cataplexy. Currently, there are no studies published to determine whether pain, migraines and headaches are just common symptoms experienced by all people with narcolepsy or whether the presence of the cataplexy symptom (and thus assumed low levels of hypocretin) exacerbates these symptoms. Also, it is unclear whether general health and wellbeing (including psychological wellbeing) is similarly affected by hypocretin levels, or may be confounded by different levels of other health symptoms, such as pain. This review poses a number of research questions that need to be explored about whether the presence or absence of cataplexy is differentially associated with different types, severity and location of chronic pain; frequency, location and types of migraines and headaches; and general health and wellbeing among people with narcolepsy. A greater understanding of the role of hypocretin in these health complaints could aid in the development of more appropriate treatments for pain, migraines and headaches amongst people with and without narcolepsy. Subjects: Psychological Science; Behavioral Neuroscience; Health and Social Care