Yesterday i saw a documentary on the tele about coma patients that miraculously recovered from their vegetative state, after they'd been given zolpidem wich is one of the most well known sleeping pills.

Anyway, i didn't see it all because eventually i became sleepy myself and went to bed, but i wonder...is there anybody who has any idea on how this works?
How can a sedative that works on GABA-receptors like most other sedatives cause coma-patients to re-awaken? It seems counter intuitive, almost like homeopathy or something....