There are medical journal articles that describe a link between CH and ADHD. Like migraines, they are a vascular headache and they are just as debilitating, often striking daily for months.

For many sufferers they are like a fire that begins behind one eye and cause it to water before the pain quickly spreads to the temple, jawbone and even teeth on that side of the face.
Normal painkillers often have no effect. Instead the first line medications constrict the blood vessels that press against the trigeminal nerve. The same medications are often used for migraine too.