…For cluster headache, the meta-analysis found a circadian pattern of headache attacks in 71% of people. Attacks peaked in the late hours of the night to early hours of the morning. During the year, people had more attacks in the spring and fall. On the genetic level, cluster headache was associated with two main circadian genes, and five of the nine genes that increase the likelihood of having cluster headache are genes with a circadian pattern of expression.

People with cluster headache also had higher cortisol levels and lower melatonin levels than people without cluster headache.

For migraine, the meta-analysis showed a circadian pattern of attacks in 50% of people. While the peak for attacks during the day was broad, ranging from late morning until early evening, there was a circadian low point during the night when few attacks happened. Migraine was also associated with two core circadian genes, and 110 of the 168 genes associated with migraine were genes with a circadian pattern of expression.

People with migraine had lower levels of melatonin in their urine than people without migraine. In addition, melatonin levels were lower during a migraine attack…