What Causes It?
Scientists consider hypnic headache a primary headache disorder, as it has no apparent underlying cause.
It tends to occur during the rapid eye movement (REM) portion of sleep, when dreams occur and brain activity is high. Thanks to this elevated brain activity, scientists believe that areas of the brain that process pain may be more stimulated during REM, leading to this unique type of headache.
Another theory is that hypnic headaches may be caused by a disturbance in melatonin. Melatonin, the “sleep hormone,” is regulated throughout the day; it’s felt that a disruption could lead to lower melatonin levels and cause headaches at about the same time each night.
What Are the Symptoms?
Hypnic headaches — dull or throbbing pain on one or both sides of the head — characteristically strike between 1 and 3 AM, awakening the individual and lasting for at least 15 minutes. Most people report having them for at least 10 days in a month. Accompanying symptoms may include nausea and a hypersensitivity to light and sound.
How Is It Diagnosed?
While certain symptoms of hypnic headache resemble other headache disorders such as migraine or cluster headaches, this condition occurs only during sleep. Of all patients seeking medical attention for headache, it’s believed that just .07% qualify for a hypnic headache diagnosis, making it challenging to diagnose and manage.
The diagnostic criteria for hypnic headaches are:
- Head pain should develop only during sleep and lead to awakening.
- Head pain should occur at least 10 days per month, for at least 3 months.
- Upon awakening, each episode should last at least 15 minutes (up to 4 hours).
- There should be no associated cranial autonomic symptoms (such as eye redness, eyelid swelling, or excess tearing) or restlessness
How Is It Treated?
Interestingly, a cup of coffee before bed can actually be effective to help people with hypnic headaches sleep through the night. Coffee, caffeine pills, or pain medications containing caffeine can also provide pain relief after the headache has already started.
For some people, taking prescription indomethacin, a non-steroidal anti-inflammatory drug (NSAID), before bed can also help to manage hypnic headaches.
Is It Preventable?
Treatment options such as caffeine, lithium, and indomethacin are considered preventive medications. Although more research is needed, it’s also been reported that melatonin usage (3-5 mg) might help to regulate and improve sleep, and reduce headache intensity and frequency.
