I am on Zoloft and it works great for me, but it depends on the person. Like anything, meds work for some and not for others. He doesn't feel any difference at all? For some people it takes a while, but since it has been a few weeks, I would have him call his Dr and ask what he thinks. I know how frustrating it can be to sit and wait for things to work. My boyfriend has been on several differnt meds and still hasn't found one that helps him. Just make sure to call the dr or his nurse and maybe set up another appt. to switch meds. Good luck!
