Over time, with any steroid I assume, but I always run testosterone; I'll eventually run into the problem of migraines that come on during physical exertion while on cycle. They usually subside for the most part afterward, but it takes time--too much time.
I've found mine are directly linked to high red blood cell count, so I've gotten into the habit of giving a pint of blood as needed and I take topamax to help out as well. Problem solved in my case.