an e-mail comes in and you just have to read it. >> your addiction to your phone may have a scary side effect that you might not remember in the morning. >> you've heard of sleep walking and sleep eating, but now there's a new phenomenon affecting people all over the globe, it's called sleep texting. dr. michael gelb of the gelb sleep center in manhattan studies sleep disorders. >> kids and a lot of adults have iphones, androids, they always have the phone. as a matter of fact, you feel the buzzing in your pocket even though there's no phone there. you just sense that there's something, a sound going off because we're so attached to our phones that the line is blurred between wakefulness and sleep. >> reporter: the disorder is most prevalent with people using a sleep medication like ambien. it happened to kristen chenoweth. >> i had a bad experience. as we all know haiti was a devastating thing to see. i was watching it one night on ambien. then i tweeted that i was going to adopt a baby from haiti.