I don't know what it is but I used to be prescribed Valium and although they did affect my brain, kind of laid back feeling and so on. Xanax, even a small amount, lays me out. Absolutely puts me asleep with in 15-20 minutes max. Sorry if this is too off topic but would anyone have a clue (I think I took a half a mg). Never had anything like it, not even 10-20 mg of Ambien put me out like that! Sorry, and thanks!