G'day sen,
Long time no chat. I hope you're doing well there!

I remember reading about Clinical Trials with GABA and Tourette Syndrome. I think that the TSA-USA was involved. It was a few years back now.

There was another thread here regarding GABA. You may have seen that already. We've not used it here at home, but I know other people have. Hopefully you'll get some advice and maybe directions to other information soon.
http://neurotalk.psychcentral.com/showthread.php?t=5979

take care,
Lara