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Ambien is a highly effective medication to help people sleep. But it's very easy to become dependent, so using it beyond a few days is asking for trouble. "Once you start taking Ambien regularly, it's almost impossible to fall asleep without it," he says. "If you take it for weeks, months, or years, you might have terrible insomnia that lasts for weeks."

Kolody says Ambien can also make you more anxious during the daytime and, worse, do crazy things when you think you're asleep. "It makes you hungry and gives you amnesia," he says. "So you might raid the fridge in the middle of the night, make a huge mess, and then in the morning think, 'Who the hell raided my fridge?' It's dangerous to have those blackouts." There have also been several reports of Ambien users hopping in their cars the middle of the night, getting in wrecks, and waking up in the emergency room with no recollection of what happened.