I have been on Effexor for over 20 years and it seems to become less effective with time. It worked at first but I seemed to develop a tolerance. I was up to 300 mg at one point and It caused problems with my adrenal system and I had to stop for 2 years. When I resumed taking it I had the same problem, I'm taking 225 now and it's not working as well as it used to. Anyone else have this experience?