Hope you don't mind me chiming in on this. Wellbutrin or bupropion is what is called a NDRI. This stands for norepinephrine-dopamine reuptake inhibitor.

It actually doesn't effect serotonin. It is commonly added on to regimens that include SSRI's such as sertraline or Zoloft since they both affect different neurotransmitters. Since wellbutrin doesn't effect serotonin, it doesn't cause the weight gain or sexual dysfunction that SSRI's do.

The biggest risk with wellbutrin is a rare side effect of seizures.

Hope this helps!