I took Effexor at 150 mg for almost 10 years. Took it for Depression and Anxiety, and for so long it worked wonders. But, I was tired of being a slave to the meds and one day I decided I wanted to stop, I needed to stop being controlled by them. I was no longer the person I had been, but it wasn't necessarily a good thing. I weened with my doctor's approval and supervision. I experienced the WORST DP I ever had in my life during the months (yes, months) it took to ween down off that medicine. Since then, the depression hasn't been as bad, but the anxiety is worse than it ever was. DP is in and out, I'm not suffering for months at a time, but it definitely comes in often for brief stints. If the Effexor works for you, I would not worry so much about what the amount is.
Sometimes, I wish I had never gone off of it, but for now, I'm living and surviving. But the anxiety remains.....and the DP remains.....and my constant wonder if I made the right decision remains.....
Hugs to you!