Basically, it’s about melatonin, the hormone produced by the body that affects sleep patterns. That bright light from your phone is not allowing your brain to do its natural work, allowing you to fall asleep. It’s keeping you awake and making you crazy. Put it down before bed. And listen to Dr. Dan Siegel from the UCLA School of Medicine, interviewed by Business Insider, as he talks about the affects screens have on your sleep. And your sanity.