Chronobiology and Sleep in Cluster Headache.

Background Cluster headache attacks follow a striking circadian rhythm with an intriguing influence of sleep. We aim to investigate differences in sleep quality, chronotype, and the ability to alter individual sleep rhythms in episodic and chronic cluster headache patients vs controls. Methods Cluster headache patients and non-headache controls from the Dutch Leiden University Cluster headache neuro-Analysis program aged 18 and above completed web-based questionnaires in a cross-sectional study. Results A total of 478 episodic, 147 chronic cluster headache patients and 367 controls participated. Chronic cluster headache patients had more often early chronotypes than controls, as measured by mid-sleep phase (P = .021 adjusted B -15.85 minutes CI -29.30; -2.40). Compared to controls, chronic cluster headache participants were less able to alter their sleep rhythms (P < .001 adjusted B -1.65 CI -2.55; 0.74), while episodic cluster headache participants reported more difficulty in coping with reduced sleep (P = .025 adjusted B 0.75 CI 0.09; 1.40). Sleep quality was reduced in both types of cluster headache compared to controls ("poor sleepers": 71.4% (105/147) in chronic and 48.3% (235/367) in episodic cluster headache vs 25.6% (94/367) in controls; both P < .001; episodic adjusted B -1.71 CI 0.10; 0.32; chronic adjusted B -0.93 CI 0.24; 0.65). Conclusion Sleep quality is decreased in both episodic and chronic cluster headache, most likely caused by cluster headache attacks that strike during the night. Episodic cluster headache patients report more difficulty in coping with reduced sleep, while chronic patients are less able to alter their sleep rhythm. Although not directly proven, cluster headache patients will likely benefit from a structured, regular daily schedule.