Never tried it go to sleep, but heres an interesting, but unrelated to your question, story about Kava Kava
One of my cousins married a guy who is half Samoan and half Korean. Most of his close family is Samoan, real big fuckers. Well, one time I went to visit them in northern Cali and it happened to be some kind of Samoan holliday. Apparently, in Samoa, on this holliday, the village priest or elder prepares Kava Kava root as a drink, and is considered a spiritual drink. So, obviously, there is no tribe elder here, so the oldest of the fam got to prepare the drink. The kava root is ground into a fine powder and placed inside a cloth. The cloth is summersed in water and drained, this is repepated over and over until all the "good" stuff from the kava is drained. We sat in a circle and the kava was pased around one person at a time. We drank out of a bowl that was half a coconut. Each time a person was served, the entire group had to chant "kava kava" then the person would drink. Once the drink has gone around the group once, if anbody else asks for another drink, the entire group has to drink. You also ask for another drink by chanting "kava kava". The drink tastes like dirt, so I was chasing it with a beer. Apparently, this is a strong intoxicant and i was not aware of it. After two rounds, most of the circle was done, but I kept asking for more and each time I asked for a drink, the entire circle had to drink too. After a while, these guys started passing out and getting real fucked up. I didn't understand because I was not that buzzed and i kept drinking after the kava was finished. I sure felt like shit the next day though.