Wow. There is a LOT of information here that I didn't know. I'm going to suggest to my son that he borrow his sister's cat for a while to see if it will help his migraines :)
We have our adult daughter living with us, along with her three cats. Only one is really cuddly, and he seems to have latched onto our youngest daughter now. I'll tell her that all of that purring is good for her, too!
Cats also have a way of going where they are needed, too...