Oh god, I found a really depressing news story:
http://www.cbsnews.com/stories/2007/09/25/earlyshow/contributors/tracysmith/main3295276.shtml(Watch the video)
The last statement was so terrible, saying there were studies on rats that found it to cause depression. Ridiculous, I'm sure they schemed that one from the paper called "Depressive-Like Effects of salvinorin A", which has nothing to do with actual clinical depression. Its a property of many pharmaceutical chemicals that are in many cases used to
treat depression. I think this went on national TV too

The good thing is no one wants to ban it due to medical potential. Even that guy interviewed from the DEA said a ban would be undesirable.