Unfortunately they haven't investigated it fully (or as much as we would like), but I've found a few anecdotal reports of people being "prescribed" kava (most likely in the form of a gelcap extract or tincture).
There is certainly significant evidence for its anxiolytic, somnolent and local anesthetic effects, but unfortunately, most popular consumer-oriented websites (ie. webmd, drugs.com, etc) overshadow the beneficial aspects with all the hepatotoxicity nonsense. Even a significant amount of peer-reviewed articles cite renal and liver damage amongst the article, without regard to the aim of the study. Until we can have more systematic reviews addressing these claims in particular, it's unlikely it will become prescribed by any MD. Most, I would bet, would hear Kava and immediately say "Oh, you can't take that, it will ruin your liver. Here have some Xanax. What's that? Oh no, it's not addictive and has very few side effects."