Have you ever awoken and turned off your alarm without knowing it, or woken up suddenly and didn't know where you were? Then you're probably among the 1 in 7 Americans who suffer from "sleep drunkenness," according to a study published yesterday in Neurology. Bouts of the condition involve waking up with extreme confusion, disorientation and sometimes even amnesia. Experiencing this "confusional arousal," as the study's authors from Stanford University call it, lasts for less than five minutes in 37 percent of people, and lasts five to 15 minutes in another 33 percent of people. The phenomenon was found to be more common in people with mental disorders like depression.