I was on Prozac after a bout with depression many years ago. I heard about a study that showed people on Wellbuturin had a greater chance of success in sticking with a diet than those that were not taking it so I asked my doctor to put me on Wellbutrin. That was back when you had to take 2 a day, rather than the once a day time release that's available now. At that time, it did work and I lost like 40 pounds using Wellbutrin and going to Weight Watchers. So it's not that it makes you lose weight necessarily, but it can help some people stick to a plan better if they're dieting.
I got off of Wellbutrin after a while, but after my second child, I had post partum depression so they put me back on it, but that time, they put me on the time release version and it did NOT have the same effect. It got rid of my post partum depression ok, but I tried getting back on WW again and I lost no weight. In fact, I gained weight. A lot of weight.
A couple years later, I felt those old familiar feelings coming back so I asked my doctor to put me back on the antidepressant. She prescribed the time release Wellbutrin again but my co-pay was very high for that version so I requested a scrip for the generic version that is now available, which again is not the time release type (have to take twice a day) and again, it's helping me to stick to my diet plan and I've lost over 20 pounds.
So, moral of the story is, every med can work differently for different people. Even different versions of the same drug can work differently. If you begin taking it and don't feel a significant difference, don't be afraid to let your doctor know. A different med, or even a different version of the same med may work better for you.
Good luck!