Unwanted long effect.
They reckon up to 6 hours, but this is taking the piss.
( Dave Trouser ; the people's choice - 75% agree, Tue 9 Jun 2009, 2:36, archived)

You've still got your own body's response to being up all night too.

( Master Of Turnips. Only gays and morons believe in ghosts., Tue 9 Jun 2009, 2:45, archived)

I don't think it's helped matters.
Also, I am used to not sleeping for other reasons. This one is a definite chemical buzz.
( Dave Trouser ; the people's choice - 75% agree, Tue 9 Jun 2009, 2:52, archived)