I remember watching a documentary many years ago about people on a study with cluster headaches who were taking shrooms. It had a surprising affect on them. If they took shrooms once per month the frequency and severity of their headaches was reduced significantly according to almost all on this study.
I found that interesting because a long time friend of mine suffered from cluster headaches since he was a kid, he was born to deaf parents and doctors theorized it may have had something to do with genetics. More interesting that he was a recreational marijuana, shrooms and acid user. Also interesting that he broke from reality in the last 5 years of his life and went into seclusion. He was killed on Monteagle a few years ago, suicide by cop. Tragic story.