Sleeping pills may cause patients to eat in the middle of the night–with no memory of it in the morning.

Of all the strange nocturnal behaviors that have been reported with the use of Ambien and other prescription sleep drugs—acting out, sleep walking and talking, and even driving while asleep—the most prevalent by far is sleep eating. Though the side effect is rare overall, most sleep doctors have heard a few stories of refrigerators being raided, ovens left on through the night, or strange food appearing in the bedroom.

Many of these sleep-eating patients take Ambien, although it's not clear whether this particular drug really is more likely to cause sleep eating, or if it's just that more cases are reported because so many more people take Ambien than any other sleep medications.

For some, the strange side effect is unacceptable: They may gain a significant amount of weight, or worry about operating kitchen appliances while sleeping. For others, like Rebecca Wiseman, 26, of Sumter, S.C., sleep eating happens only occasionally—and it's a small price to pay for the relief that medication can bring.

Relief from hospital-induced insomnia

Wiseman starting taking Ambien while she was in the hospital on bed rest during her second pregnancy. She was grateful for the full eight hours of sleep it got her, and took a pill just about every night for six weeks.

She's not sure exactly when the strange nighttime behaviors started, but she first realized that something was unusual when her doctor asked her about something that had occurred the night before—she'd had some troublesome symptoms and her mother had gone to get a nurse. She had no recollection of this.

"I was scared; what if something had really gone wrong and I had no memory of it?" says Wiseman. "The doctor told me it was a common occurrence though, so I was a little relieved. And I knew I was constantly being monitored by nurses, so they would know if something happened."

This changed, however, when she left the hospital and returned home with newborn twins. Wiseman's military husband worked long shifts and needed sleep, so she didn't take medication on nights when she had to be up with the babies. But she struggled with so little sleep and looked forward to the two or three nights a week when her husband didn't work the next morning so she could get good rest with Ambien.

Morning surprises

Then she started raiding the fridge. "I have no idea when it started happening, but one morning I woke up with milk and cereal all over me," she says. "Somehow during the night I'd gone downstairs and fixed a bowl of cereal—then climbed back into bed and dumped it all over the front of me. Another time I found a plate of half-eaten dinner at the foot of the bed: I had fixed a plate, heated it up in the microwave, and then gone back to bed to eat."

Wiseman, who had gastric bypass surgery about four years ago and cannot handle large quantities of food, says she's never a binge eater during the day. "Sometimes I have flashbacks of getting sick the night before, after eating too much of the wrong food, like leftover barbecue roast beef sandwiches. And my husband, when he's tried to stop me, says I yell at him—–which is very unlike me."

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Even so, it's still worth it

But still, Wiseman relies on medication to keep her functioning. When her prescription ran out and the family moved to a new military base, her new doctor refused to prescribe more pills. She spent a few miserable months barely getting by with over-the-counter and herbal sleep aids, until she found another physician who renewed her Ambien prescription.