Just a quick note about GHB. This is a psychoactive drug so, as always, this isn't any kind of advice or recommendation.... Just a documentation.
I managed to get some to try it for anxiety and in the hope of an alternative to alcohol for social situations. It is quite strong stuff and certainly has similar effects to alcohol in terms of swaying, lack of co-ordination, and struggling for words. Unfortunately, it had few of the more pleasant relaxation or mood enhancing effects of alcohol. If anything, it had all the negatives of alcohol and not many of the positive (positives being a little more laughter and a bit hornier). there was zero hangover however.
Overall, i'd say it is not worth trying for hppd/anxiety, which is a shame, as it has some similar mechanisms as benzos.
http://en.wikipedia.org/wiki/Gamma-Hydroxybutyric_acid