how come, with all of the drug companies big advances, they can not come up with something that just adds serotonin or dopamine instead of reuptake inhibitors?

I heard some time ago that Europe did have a drug that just made you produce more serotonin, but it wasn't available here. Will try to find it again, but what do you SAD, CFS, fibro suffers think?

I ask in this forum, because usually that is the dr. first line of defense, it seems.