It's a very interesting and educational piece, but I also think that it can be a bit misleading. For instance, the authors note that "The pathophysiological effects of kava include muscle degradation, kava dermopathy presented as scaly skin rashes, urticaria, sebotropic eruption, meningism, depression/suicidal tendencies and hepatotoxicity". These are very serious accusations that one would hope would be backed up by credible studies. Unfortunately, the quality of some of the references leaves a lot of be desired. For instance, the claim that kava might result in depression/suicidal tendencies is made by a group of scientists from New Caledonia who observe "association" (but no causality) between regular kava drinking and depression. They do not consider the fact that people suffering from depression might be generally more likely to consume mind-altering substances. Also, few of the quoted studies pay sufficient attention to the issue of kava products' purity, nobility and quality. This is quite bizarre. It seems that many of the kava studies look at the effects of consumption of anything that people will call "kava". It's like studying the effects of alcohol use without paying any attention to whether it's ethanol or methanol, whether it's beer or industrial ethanol and whether it is consumed with caviar or cement. No wonder there are so many inconsistencies and weird results.
I bet that few, if any, of these quoted negative effects could be observed among the users of 100% noble and pure kavas prepared in a traditional way.
In general, a very interesting review, but it would be even better if the authors had more critically examined some of the sources they quote. Many thanks to
@Gourmet Hawaiian Kava for sharing it with everybody.