Effexor is unforgiving. If you don't take it at exactly the same time each day, it's possible you are going beyond the half-life and it is triggering the brain zaps. Or, it may be a dosage issue. I loved effexor for my depression. It really worked quite well, but getting off of it was a bit of a hassle. It took a few weeks but I was able to get off of it without any lasting problems.