I don't think it's doing anything for me, except some side effects. I'm past the 30 day mark, on 75mg, and I don't think it's done anything, despite a few minutes here and there where I wonder "could it be helping?" But I realize it's probably placebo. It appears I hadn't done enough research.
On another forum there's another person like me who's had a "pressure-like sensation" for 5 years--I've had mine for 7--and she's diagnosed with NDPH. She's tried over 50 meds including Topamax and can't find adequate relief. NDPH is extremely hard to treat, if you can do so at all. It now looks like I may very well have NDPH... possibly something Topamax can't even help at the 400mg dose. And yet there I was last time at the neurologist's office, being told there's a good chance I could take this stuff for 3-6 months, reduce the pressure significantly, and then get off all the meds. I guess I'm gonna have to ask a lot of questions, next time I see the neuro.