The Associated Press has a huge article on the latest bipolar disorder treatment studies. The article runs through a variety of new (and some old) approaches including scopolamine (a drug for seasickness), electric fields like those in brain-scan machines, riluzole (a drug for ALS), and tamoxifen (a breast cancer drug). I think that this report, which also has a ton of information on what bipolar disorder is and how some people experience it, highlights the vast amount of money and effort that is going into finding effective treatments.
I don’t have numbers to back this up, but I would imagine that among mental disorders, bipolar disorder is one of the top 5 most researched disorders at the present time. A lot of this would be related to the dramatic increase in people being diagnosed with bipolar disorder and the potential for new profits for the next great drug therapy. This is where articles like the one John wrote about here make the picture of best practices in mental health blurry and confusing.