For Ken and Bernice Patterson, a light-hearted game of cribbage makes for a cozy afternoon. Ken's good nature shows through even when he's losing. "I hate that game," said Ken Patterson who has a sleeping disorder. So it may surprise you that this happy-go-lucky, pleasant guy turns into a violent and aggressive bully when he's asleep at night. "I didn't know what I was doing," he said. Dr. Brad Boeve and his colleagues study patients with RBD, which stands for REM behavior disorder. He says for years people did not even recognize that condition as a medical problem. "This is real, diagnosable, and its treatable in most individuals," said Boeve. REM behavior disorder is caused by abnormalities in some circuits in the brain stem. Before Ken went on medication he always had bruises and injuries because he repeatedly leaped out of bed. "It's like bailing out of something. Out of bed, out of an airplane, out of a car," said Ken. But thanks to daily medication, the cheerful and gentle man during the day tends to stay that way all night.