Wellbutrin basically got me diagnosed! Most of last year I was severely depressed and anxious, so my GP put me on it after trying SSRI's/SNRI's that didn't work (this was before I was diagnosed with bipolar). At 150mg it did nothing. At 300mg it helped quite a bit - I was able to at least do things like go grocery shopping and do some actual work instead of just sitting in front of my computer staring at it. Sometime in there I started seeing a psychiatrist, and since I was still having anxiety issues, she upped it to 450mg. I'm not sure if I was due for a hypomanic swing or if the meds caused it, but it took maybe a week to kick in, and I felt pretty damn good. I was able to keep a lid on my enthusiasm during my 1-month follow-up with her, so we decided to keep it there. Then about two weeks after that (so, about 6 weeks after I went up to 450mg) things went a little haywire. Basically everything you see on a symptoms checklist for a manic episode, that was me, except I managed to stay out of the hospital/jail. I did come extremely close to checking myself in though, because it got to the point that I wasn't physically able to stay still, thinking was out of the question (I looked back the other day at something I wrote at the time and it makes almost no sense) and I was hallucinating. Sooooo I got an emergency appointment, which I don't remember all that clearly though I remember her seeming pretty alarmed that I had gotten a pixie cut since my last appointment. She pulled me back down to 300mg of wellbutrin and started me on lamictal. Since then I've still felt pretty 'up' most days but not out of control.

So yeah, for me once I got to 300mg it did kick in pretty quickly, and going past that had an almost immediate effect. It also demolished my appetite for a couple weeks with every increase, so that was a welcome side effect.