Scattered throughout past sleep research are a number of reports describing unusual behavior while sleepwalking, including sleep eating, sleep phone calls, sleep sex -- and even sleep rape and murder.

Now, a new case study is adding one more bizarre sleep phenomenon to the literature: sleep e-mailing.

In an article published in the journal Sleep Medicine, Seton Hall University researchers document the case of a 44-year-old woman who struggled with severe insomnia for years before she was prescribed the popular sleeping aid, zolpidem (also known by the brand name Ambien), in 2004.

The zolpidem helped with her insomnia at first, but the effects of the drug began to wear off after a period of time. Soon her doctor increased her dose, allowing her to get five hours of sleep per night.

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