I would offer this Wiki link - with the statement that, although I know all Wiki links should be regarded with caution, this does offer much information that is showing good information from much literature out that about GABA studies.

And I would direct your attention to the to the information in the GABA Supplements section , scroll down - "....claims are not yet scientifically proven."

bluehiroko,

You seem very adverse to taking medication - particularly those typically prescribed, and that is a choice folks can make. However, you need to make an informed choice about a Natural supplement, and stick with one for a longer term than you seem to be doing.

Most herbal supplements such as Valerian, Melatonin, L-tryptophan have been used in anxiety, sleep aid, claims for antidepression have been made with them, etc.

Feverfew has been used for Migraines.

I would however advise caution in using something with no proven basis in science that is supposed to affect your brain's chemistry - you have enough problems with that with your injury.