Background and objective: Narcolepsy is a rare disease which remains undiagnosed in 90 %. The international literature so far has paid little attention to comorbid disorders.
Patients and methods: In preparation for a German Narcolepsy Register this pilot study evaluated data from hospital records of 106 narcolepsy patients (60 men, 46 women, 8-83 years, mean 45.1 years) retrospectively emphasising comorbid diseases.
Results: The parasomnias sleepwalking and nightmares were 6 times as frequent as in the general population. With respect to the HLA findings the extremely high frequency of REM behavior disorder contributes to the assumption of a common pathomechanism. Obstructive sleep apnea and periodic limb movement disorder (PLMD) occurred much less than described in literature, while the results on obesity, headache and depression are in line with published findings.
Conclusion: Diagnosis of one of these comorbid disorders should always be followed by thorough investigation for symptoms of narcolepsy i. e. excessive daytime sleepiness, sleep attacks and cataplexy.