- According to Ohayon's study, just being a woman increases the chance of getting chronic morning headaches, but the reason why is unclear, although women also get migraines three times as often as men.
- It used to be thought that most chronic morning headaches were caused by sleep problems or by grinding the teeth while asleep. Ohayon's study disproved that, but sleep problems or teeth grinding can still be a cause.
- People with clinical depression or sinus congestion also have chronic morning headache. In these cases, the headaches won't go away until the primary condition is treated.
- According to MAGNUM, the National Migraine Association, dependence on drugs like caffeine, painkillers or opiates can cause predictable morning headaches in the very early morning hours.
- According to Ohayon's study, people who were unemployed suffered more from chronic morning headache than those with jobs.
